AFR Installation Instructions

Read our instructions before installing your AFR product.
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Titon Manifold

  1. Installation Instructions

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Small Block Chevy Aluminum Cylinder Heads

  1. Installation Instructions

    ATTN: Please read through all instructions before attempting cylinder head installation.

    Important: Apply anti-seize to all bolts and spark plugs to ensure a long thread life.

    *WARNING* Piston dome to cylinder head clearance must be checked prior to final assembly of engine. Compression Ratio and Piston to Valve clearance must be checked before final assembly

    Cleaning:

    AFR thoroughly cleaned your heads prior to shipment. Your heads were washed in a water soluble chemical agitation tank and blown out with high pressure air 3 to 4 times before they were boxed. However during some machining operations chips are packed and wedged into the water jacketing and occasionally come loose in transit. Keep in mind one chip the size of a dime breaks into hundreds of tiny chips and makes the situation appear much worse than it is in reality. It is not unusual if you blow high pressure air into the water jacketing to see additional foreign debris, or chips finding their way out. AFR recommends that you thoroughly blow out your heads prior to installation.

    Head Gaskets:

    Fel Pro #1003 for all aluminum heads up to 4.100” bore. Fel Pro #1034 should be used for 4.100” or larger bore. Applications requiring steam holes should use Fel Pro #1014. Late Model LT-1 reverse cool applications use GM gaskets or Fel-Pro #1074. AFR has removed the cooling passage between cylinders #1 & #3 and #5 & #7 to increase strength of the casting. Do not drill these areas out in an attempt to find water jacketing.

    Intake Gaskets:

    Important: Do not port match you intake manifold to below gaskets, as they do not exactly fit AFR cylinder heads.AFR #6820 gaskets Fel-Pro #1206 should be used for 210, 220, 227, 235 & 245 heads. AFR #6810 gaskets Fel-Pro #1205 should be used on the 195 street heads, the 195 competition PKG heads use AFR #6820 Fel-Pro #1206. We recommend AFR #6817 gasket Fel-Pro #1256 for 180 heads. A small amount of silicone is recommended around the water ports and the bottom of the intake ports. For 180 LT-1 reverse cool applications use GM gaskets or Fel-Pro #1284, for AFR 195, 210 & 227 LT-4 use AFR #6860. On some applications it is advised to eliminate the cork end gaskets and use a bead of silicone instead. Do not port match your manifold exactly to the gasket–leave .050” per side smaller. Do not port match your intake manifold to the above Fel-Pro gaskets because Fel-Pro doesn’t precisely fit AFR heads.

    Exhaust Gaskets:

    Fel-Pro #1404 exhaust gaskets should be used on all street heads (180 & 195). With minor trimming Fel-Pro #1406 may be used on the 210, 220, 227 & 235cc standard exhaust heads. For spread-port heads Fel-Pro #1409 should be used. Do not under any circumstances port match exhaust ports to match gaskets. Reverse cool applications use GM gaskets only.

    Valve Cover Gaskets:

    Fel-Pro #1604 double thick cork with steel core is recommended. For center bolt applications, use GM factory replacement gaskets. To ensure proper seal on perimeter bolt valve covers, it is necessary to fill the slotted bolt holes with silicone.

    Head Bolts & Washers:

    Quality relief ground bolts or studs are preferable. You must use a washer between the heads and the fastener to prevent galling.

    Head Bolt Torque:

    All aluminum heads should be torqued to the bolt manufacturer’s specifications. This should be done in the proper General Motors sequence in 10 ft./lbs. increments beginning at 40 ft./lbs. Moly lube should be applied between fasteners, washers and area around head bolt to prevent galling and improper torque values. All high-compression, supercharged, turbo-charged & nitrous motors should receive a re-torque after the first running and complete cool-down. Bolts containing a 12-point head are suggested in 3 areas on each head near the exhaust valve springs where it may be difficult to fit a standard 5/8 hex-head socket. In case of head studs use 12 point nuts. Air Flow Research stocks complete and partial head bolt kits, studs, and washers for your convenience. Proper ARP #’s for head bolt kit use #134-3701 and head stud kit use #234-4301. Sealer should be applied to all thread areas that enter into the block water-jacketing. Permatex is a good general purpose sealer. These are general guidelines, check directly with the manufacturers of fasteners for exact torque specifications.

    Rocker Stud Location:

    Air Flow Research heads feature two rocker arm studs locations, standard GM and an offset (for maximum intake port volume). The 180, 195, 210 & 220 heads all use the standard GM L98 stud locations. The 227 & 235 heads use the offset location that will require a matching stud girdle. Air Flow Research stocks both standard, offset girdles and adjusting nuts for your convenience. The 245cc is a shaft mount rocker system only.

    Guide Plates:

    Use only the adjustable guide plates supplied by Air Flow Research! Pushrod guide plates are furnished with each set of AFR aluminum heads. Studs should be torqued to 55 ft./lbs. Silicone sealer is recommended on applications where the stud hole intersects the intake port.

    *IMPORTANT*

    5/16 thick wall Chrome Moly heat treated push rods should be used to avoid wear of the pushrod from contact with the guide plate. If using a tall lifter/short pushrod (6.150 0.L.) combination the 227/235 will require some clearancing near the head deck surfact. Do not clearance any higher than needed or you will break into the intake port.

    Pushrod Lenght:

    This seems like an easily answered question, however, there are many variables. Block and cylinder head deck heights, head gasket thickness, varying cams, rocker arms, and valve length can all affect pushrod length. Please see our following best estimates: for 180 and 195cc heads typically a standard or .100” long pushrod works. For 210, 220 & 227, 235cc or 245cc typically a .100” or .200” long pushrod will usually achieve proper geometry. For exact pushrod length we suggest using an adjustable pushrod to determine the proper length pushrod. For detailed information on pushrod lenght, please view the FAQ section of our website.

    Rocker Arms:

    The Air Flow Research 180, 195, 210 & 220 aluminum heads are designed to use standard pushrod location rocker arms (offset rockers are not required). Clearance between rocker arms and the retainers should be checked. For high RPM stability, the Jessel or T & D shaft systems are recommended. AFR stocks a complete line of standard and shaft rocker arms for your convenience. AFR suggest for the 227 & 235 you use a shaft mount rocker and offset lifters or a .050” offset intake rockers. With the .050” offset the intake rocker arms will be at a slight angle and the roller tip will not be perfectly parallel or centered on the valve tip. The 245cc only accepts a shaft mount rocker system with an .180” offset intake lifter required.

    Important Note: Do not use late model rocker arms containing side rails as they will conflict with the AFR guide plate.

    Valve Springs:

    It is the customers responsibility to check and make sure that spring pressures are correct for his Cam

    Valve Guide Clearance:

    Intake & Exhaust guide clearances are .00125. On some severe applications with heavy nitrous, marine or blower usage, looser guides might be required, looser guides isn't an option AFR offers.

    Valve Tips:

    Do not grind your valve tips. Some AFR heads have hardened stellite tips which cannot be reground. If ground the tip will mushroom over causing severe damage. If your valve tips are magnetic you can grind a maximum of .015” from the tip.

    Valve Seats:

    Both intake and exhaust valve seats are heat-treated and compatible with unleaded fuels.

    Spark Plugs:

    (14mm x 3/4” gasket) no tapered seat style! For race applications Autolite 3910 or equivalent is a good starting point. For street application Autolite 3923 or equivalent is a good starting point. Please view manufacturer catalogs to find equivalent spark plugs. Plug selection is a choice dictated by many factors including rpm level, compression ratio and type of fuel. The above plugs are a starting heat range; blowers, turbo or nitrous applications usually require 1 to 2 heat ranges colder. Spark plug gap should be determined by the ignition manufacturer. You can cross reference to your favorite brand if desired.

    400 Blocks:

    Steam holes are recommended for all 400-block applications. Use a 400 gasket as a template and drill the three holes nearest the spark plug side of the head straight down, the other three which are very near the head bolt holes should be drilled at a 30 degree angle away from the bolt hole. The center hole will intersect water about 1” down and the two outboard holes to a depth of 2 1/4”. Use 1/8” drill.

    Coolant:

    It is important to maintain a 50/50 mix of antifreeze in the cooling system to prevent corrosion of aluminum heads. Don’t use tap water use distilled water, most supermarkets have purified or distilled water. Check labeling to verify purified through deionization.

    Air conditioning & Alternator Brackets:

    Late model vehicles with one piece brackets that bolt to the block and cylinder heads, may find it necessary to elongate the holes in the brackets to obtain proper hole alignment. Severe production variances from the O.E.M. as well as block and cylinder head milling will all affect this relationship.

    Porting Instructions:

    Polishing ports will not improve performance. The center head bolt hole and push rod cross section in intake ports are very thin/maximized from AFR.

    Torquing:

    We suggest not using a torque wrench on intake and exhaust manifold bolts, accessory bolts, or spark plugs as inaccurate torque wrench values can easily strip the smaller threads. Just snug up hand tight with a wrench only.

    Intake Manifold:

    Pre-Eliminator (2006 and before) AFR 210 & 227s have extra material on the intake interface of the heads. This raises the intake manifold approximately 3/16" higher than normal. Make sure that your oil pump rod properly engages the oil pump and that your cam and distributor gear alignment is correct. Also a large gap might be present between the end rails of the block, AFR sells spacers to remedy this.

    TITANIUM VALVES:

    If you have upgraded to AFR Titanium valves in SB Chevy, SB Ford or BB Chevy applications they are coated with Chrome Nitrate (CrN) on the stem and seat area for longevity purposes. This is the same coating GM uses in the LS7 ZO6 applications and is designed to last 50,000 plus miles. YOU CANNOT GRIND, REFACE OR LAP IN THE 45 DEGREE SEAT AREA. If you grind or lap in the valve, the coating is removed and the seating area on the valve seat will wear prematurely reducing the service life substantially.

Big Block Chevy Aluminum Cylinder Heads

  1. Installation Instructions

    ATTN: Please read through all instructions before attempting cylinder head installation.

    Inspection:

    Check all machined surfaces for nicks, burrs, etc, that might have occurred during shipping or storage. If necessary, carefully dress with a file, or sandpaper supported flat by a straightedge. This is especially important on the head deck and intake manifold flange to have an effective trouble-free gasket seal.

    Valve Springs:

    It is the customer’s responsibility to check and make sure that spring pressures are correct for his/her camshaft application. We recommend a minimum of .060” clearance from coil bind at full valve lift.

    Valve Guide Clearance:

    Our typical valve guide clearances are .0013”-.0016”. In some severe applications (nitrous, marine endurance racing, or blower usage) looser guides might be required. Check with your engine builder.

    Piston Dome Clearance:

    Piston dome to combustion chamber clearance MUST be checked prior to final engine assembly. This is especially important for pistons that have a .700” + dome height which are common on high compression 427-511 based engine configurations. Pay special attention to the crest in the chamber directly across from the spark plug. Consider .040” minimum clearance with 7000 rpm or less. Slightly more would be required for motors that are turned higher.
    Engine Bulder's Tip:With some domed aftermarket pistons, it may be necessary to slightly clearance or modify the piston due to our more modern (efficient) heart shaped combustion chamber design. Most of the newer manufacturer’s dome profiles will clear. Note that usually less than 1cc of aluminum is removed which only equates to a weight reduction in the piston of one to two grams. If your rotating assembly is already balanced, this is a non-event and creates a VERY slight overbalance which in theory brings your engine into a better balance at slightly higher RPM. While some of you might be inclined to remove the material from the actual cylinder head note that all of the combustion chamber shapes are very critical to flow and altering the cylinder head can and will effect flow and power production. The easiest way to check for this is by turning the engine over slowly with the cylinder head installed without the head gasket. See web site for more details.

    Piston to Valve Clearance:

    It is your responsibility to check and make sure you have adequate piston to valve clearance before final engine assembly. Don’t forget to check radial (side) clearance as well.

    Spark Plug Clearance:

    In the event your engine has extremely tall piston domes, it might be necessary to index the plug electrodes and/or slightly clearance your piston domes to provide a minimum of .060” from piston dome to electrode tip. Do not use projected tip plugs with extremely tall dome designs (unless you are certain you have enough clearance).
    Note: While on the subject of clearance, it is vital that you check clearance of ALL moving parts due to the vast array of rocker arms, lifters, cams, springs, etc. Don’t forget to check pushrod to head clearance as well as any potential interference from your rocker arms and spring assemblies prior to final engine assembly.

    Rocker Studs:

    AFR BB Chevy heads require two different length rocker studs. The (8) shorter studs (referring to the coarse thread length that screws into the head) should be installed on the intake side with a small amount of teflon or some other non-hardening thread sealer. Conventional bolt thread lubricant can be used on the longer (8) exhaust studs. Never use a shorter stud on the exhaust side.
    Note: Torque Rocker Studs to 55-60 ft/lbs.

    Valve Seats:

    Both intake and exhaust valve seats are heat treated ductile iron and are compatible with unleaded fuels.

    Guide Plates:

    Only AFR guide plates will properly fit our AFR Big Block Chevy cylinder heads. We carry them in stock under AFR part #6109. The Comp Cams part # is 4806.

    Pushrods:

    All AFR heads will require pushrods that are longer than stock length. The most common lengths are a +.200” to a +.250”; however, due to a large number of variables (deck height, cam base circle, lifter height, etc.) ALL pushrod lengths must be physically checked to achieve proper valve train geometry. For detailed information on pushrod lenght, please view the FAQ section of our website.

    Stud Girdle:

    All of our BB Chevy cylinder heads have been designed with valve angles rolled over two degrees from stock location to provide better flow characteristics. Stud girdles produced for stock Chevy castings as well as other aftermarket pieces that have standard valve angles will not fit properly. We stock a high quality girdle in a convenient two piece design that will fit our heads correctly. (Most girdles that fit Dart heads will also fit due to their two degree roll-over design).

    Head Studs/Bolts:

    AFR BB heads take one inch longer fasteners along the exhaust port (bottom) side of the cylinder head. AFR stocks complete kits or partial kits (studs or bolts) for the eight additional longer fasteners.
    Note: We recommend the use of studs due to the higher clamping load they place on the cylinder heads. Blown, turbo, or nitrous engines should always use studs due to the much higher cylinder pressures they create.
    Apply anti-seize to all bolts and sparkplug threads to insure long thread life.

    Recommended Gaskets:

    Head Gaskets:

    Mark IV Block 4.540 Bore Felpro 1017-1
    Note: 1017-2 is .051 compressed thickness
    Mark IV Block 4.630 Bore Felpro 1057
    Mark IV Block 4.625 Bore Felpro 1093
    Note: O-ring perfectly round, .051 thick, typical “pro-stock” style gaskets.
    Mark V-VI 4.540 Bore Felpro 1047 or 17048
    Mark V-VI 4.630 Bore Felpro 17049
    Note: All after market Merlin and Dart Big Blocks accept "Mark IV" style head gaskets.

    Intake Gaskets:

    (For best fit) Felpro #1275
    Mr Gasket #121
    Note: Only use AFR’s gaskets for port matching. Most other gaskets have a slightly larger entrance. You will see NO PERFORMANCE GAIN by opening your heads or intake manifold to the larger gasket opening.

    Exhaust Gasket:

    Felpro #1412

    Spark Plug Recommendation:

    (Flat seat with gasket, .750” long reach, 5/8” hex head)

    Autolite #3932 Race Application Standard Tip        


    Champion #C59C Race Application Standard Tip        


    Champion #C59YC Race Application Projected Tip        


    Champion #RC12YC Street Application Projected Tip        

    Note: Other spark plug manufactures plugs that will also cross-reference and fit our AFR BBC castings. Always consult with the manufacturer for heat range that best fits your application.

    Head Bolt Torque:

    All AFR BB Chevy heads should be torqued to 75 ft/Ibs. This should be done in the proper General Motors sequence in 15 Ib. increments beginning at 30 ft/Ibs. Moly lube should be applied between fasteners, washers, and area around head bolt to prevent galling and improper torque values. Sealer should be applied to all thread areas of fasteners that enter into block water jackets. Sealer is unnecessary with blocks that have “blind holes” in the deck surface and do not go into water.

    Valve Length:

    Intake Valve 5.500” (+.250)
    Exhaust Valve 5.450” (+.100)

    Coolant:

    It is important to maintain 50/50 mix of antifreeze in the cooling system to prevent corrosion of aluminum heads. Do not use tap water, Use distilled water instead. Most supermarkets sell purified or distilled water. Check labeling to verify purified through deionization.

    Head Fastener Re-Torque:

    All high compression, supercharged, turbo, and nitrous motors should receive a re-torque after the first running and complete cool-down. Be sure to back off the fastener about 1/8 of a turn to eliminate false readings from “break-away” torque. Always re-torque in the same general motors sequence you initially tightened them with.

    Valve Lash:

    Be aware that an aluminum headed/iron block combination usually requires approximately .006 tighter lash when it is cold. An all aluminum engine could be as much as .010 – .020 tighter when the motor is cold. Every motor is different, but these guidelines should get you in the ballpark.

    Valve Tips

    Do not grind your valve tips. Some AFR heads have harden stellite tips which cannot be re ground. If ground, the tip will mushroom over causing severe damage. If your valve tips are magnetic, you can grind a maximum of .015 from the tip.

    Cleaning:

    AFR thoroughly cleaned your cylinder heads prior to shipment. Your heads were washed in water soluble chemical agitation tank and blown out with high pressure air 3 to 4 times before they were boxed. However during some machining operations chips are packed and wedged into the water jacketing and occasionally come loose in transit. Keep in mind one chip the size of a dime breaks into hundreds of tiny chips and makes the situation appear much worse than it is in reality. It is not usually if you blow high pressure air into the water jacketing to see additional foreign debris, or chips finding their way out. AFR recommends that you thoroughly blow out your heads prior to installation.

    TITANIUM VALVES:

    If you have upgraded to AFR Titanium valves in SB Chevy, SB Ford or BB Chevy applications they are coated with Chrome Nitrate (CrN) on the stem and seat area for longevity purposes. This is the same coating GM uses in the LS7 ZO6 applications and is designed to last 50,000 plus miles. YOU CANNOT GRIND, REFACE OR LAP IN THE 45 DEGREE SEAT AREA. If you grind or lap in the valve, the coating is removed and the seating area on the valve seat will wear prematurely reducing the service life substantially.

Small Block Ford Aluminum Cylinder Heads

  1. Installation Instructions

    ATTN: Please read through all instructions before attempting cylinder head installation. Important: Apply anti-seize to all bolts and spark plugs to ensure a long thread life.

    Warning: Piston dome to cylinder head clearance must be checked prior to final assembly of engine. Piston might need clearance with AFR Heart Shaped Chamber.

    Note: 1986 5.0L must have pistons notched for clearance. High flow 2.020" or larger valves might require aftermarket pistons or notched stock pistons for valve clearance.

    Must be checked before assembly, heads with 2.020" valves or larger usually will not fit a piston without valve notches having proper reliefs.

    Valve Springs:

    It is the customer's respnsibility to check and make sure that spring pressures are correct for their cam.

    Valve Guide Clearance:

    Intake and exhaust guide clearance are .00125" on some severe applications (nitrous, marine, or blower) looser guides might be required

    Thermo Adapaters:

    Thermo adapters are installed for shipping purposes only. They need to be sealed, tightened and put in their proper location; proper location is the front of the engine compartment facing the radiator. If you are not using the air pump on part numbers 1402, 1422, 1420, 1426, 1428, 1472 or 1492 you must block off the open holes on the back of the heads facing the firewall with a 5/8”-11 plug or bolt to prevent an exhaust leak. The above instructions need to be done before installing the heads on the block.

    Coolant:

    It is important to maintain a 50/50 mix of antifreeze in the cooling system to prevent corrosion of aluminum heads. Do not use tap water use distilled water, most supermarkets have purified or distilled water. Check labeling to verify purified through deionization.

    Torquing:

    We suggest not using a torque wrench on intake and exhaust manifold bolts. Just snug up hand tight with a wrench only.

    Valve Seats:

    Both intake and exhaust valve seats are heat-treated and compatible with unleaded fuels.

    Accessories:

    Although AFR street cylinder heads will accept OEM components, rocker arms, valve covers, intake manifold, 7/16” bolts for 165cc head (except part #1396 & 1399) and 1/2” for 185cc, 195cc, 205cc & 220cc head, we highly recommend that premium quality hardware be used with your new heads.

    Head Gaskets:

    Use Fel-Pro #1011-1 for years 1962-95. For high compression (12:1 and above) nitrous or forced induction, consider using Fel-Pro #1006 Locwire.
    NOTE: #1006 Locwire gasket will require modification of the head deck surface by a competent machine shop to Fel-Pro specifications, also put a small amount of silicone around water cross-over in head deck when using #1006 gasket.

    Intake Gaskets:

    Use AFR #6828 on the 165cc, 185cc & 195cc intake runner head. For the 205cc use AFR #6832. The 220cc runner head will require the AFR #6812. A small amount of silicone is recommended around the water ports and the intake port. Do not port match your manifold exactly to the gasket—leave .050” per side smaller.

    Exhaust Gaskets:

    Any header or manifold gasket designed for original equipment heads will fit the AFR 165cc, 185cc, or 195cc street cylinder heads, use Fel-Pro #1415 exhaust gasket. For the 205cc and 225cc use Fel-Pro #1487 exhaust gasket.

    Valve Cover Gasket:

    Use Fel-Pro #1645 1/4” thick cork-lam with steel core.

    Head Bolts or Studs:

    High quality head studs or head bolts with hardened washers must be used to prevent galling of the aluminum head. Recommended head bolts are ARP #1543701 for engines with 7/16” head bolt holes (289 and 302 CI). Engines with 1/2” head bolts holes (351-w and 302 CI SVO) should use ARP #154-3603. For maximum head gasket clamping AFR recommends head stud kits. AFR 185cc, 195cc, 205cc & 220cc heads come with head bolt hole drilled to 1/2’’. If installing on a 289-302 block with 7/16” threads, a headbolt reducer bushing 1/2” to 7/16” must be used, AFR part #6324.

    Head Bolt Torque:

    Apply moly-oil mixture to washers, and area around head bolt to prevent galling and improper torque readings. Torque to 70 ft/lbs. for 7/16” bolts or studs (289 or 302) or 100 ft/lbs. for 1/2” bolts or studs (351W) in three or four steps following the factory tightening sequence. Then tighten the long (upper) head bolts or studs to 80 ft/lbs. (7/16”) or 110 ft/lbs. (1/2”). A re-torque is recommended after initial start-up and cool down (allow 2-3 hours for cooling). Sealer should be applied to all head bolts or studs that enter into the blocks water-jacketing system. Permatex is a good general-purpose sealer. These are general guidelines, check directly with manufacturer of fasteners for exact torque specs.

    Spark Plugs:

    Use 14mm x 3/4” reach gasketed spark plugs, no tapered seat plugs. Street application use Autolite #3924, for 205cc & 220cc race head use Autolite #3922, or equivalent. Plug selection is of course dictated by many factors including RPM level, compression ratio, and fuel type. Forced induction or nitrous applications usually require 1 to 2 heat ranges colder. Spark plug gap should be determined by the ignition manufacturer. You can cross reference to your favorite brand if desired.

    Hydraulic Lifter Pre-Load:

    With part #’s 1400, 1402, 1420,& 1422 (stud mount heads) cylinder head hydraulic lifter pre-load is easily adjustable due to the stud/guide plate design. Harden heat treated chrome moly pushrods are required with guideplate style heads. Rocker arm studs should be torqued to 55 ft./lbs. They are not torqued from AFR, torque pedestal rocker arms to stock recommendation. On part #’s 1472, and 1492 adjustments to lifter pre-load with non-adjustable pedestal bolt down rocker arms can only be made with shims as sold by Ford SVO HM-6529-A302 or Crane #99170-1. AFR recommends 1/4”-1/2” turn pre-load for hydraulic cams. Rocker arm geometry should be checked making sure that the contact point of the roller or pad on a stock rocker remains centered on the valve tip and does not roll off the edge. Visual inspection of the rockers, valve springs, retainers, and pushrods should be made to ensure that none of the components come into contact with each other. If problems with valve train exist, simple changes such as pushrod length may have to be made. Pushrod length is affected by many variables. Block and cylinder head deck heights, head gasket thickness, varying cams, rocker arms, and valve length can all affect pushrod length. Please see our following best estimates: for 165, 185cc or 195cc heads typically a standard or .100” long pushrod works. For 205 or 220cc typically a .100” or .200” long pushrod works. If pushrod to cylinder head contact is evident, loosen rocker stud and re-align guideplate as needed. See website under FAQ for detailed information on pushrod length.

    Valve Tips:

    DO NOT GRIND YOUR VALVE TIPS. Some AFR heads have harden stellite tips which cannot be re-ground. If ground, the tip will mushroom over causing severe damage. If your valve tips are magnetic you can grind a maximum of .015” from the tip.

    Alternator Bracket:

    Some years require the supplied 5/8”-11-7/16”-14 reducer to be installed into air pump thread in order to properly mount the alternator.

    Cleaning:

    AFR thoroughly cleaned your heads prior to shipment. Your heads were washed in a water soluble chemical agitation tank and blown out with high pressure air 3 to 4 times before they were boxed. However during some machining operations chips are packed and wedged into the water jacketing and occasionally come loose in transit. Keep in mind one chip the size of a dime breaks into hundreds of tiny chips and makes the situation appear much worse than it is in reality. It is not unusual, if you blow high pressure air into the water jacketing, to see additional foreign debris or chips finding their way out. AFR recommends that you thoroughly blow out your heads prior to installation.

    Pushrod Length:

    This seems like an easily answered question, however, there are many variables. Block and cylinder head deck heights, head gasket thickness, varying cams, rockers arms, and valve length can all affect pushrod length. Please see our following best estimates: for 165, 185 or 195cc standard or .100” long pushrods work in most cases. For 205 or 220cc typically .100” or .200” long pushrods will usually achieve proper geometry. For exact pushrod length we suggest using an adjustable pushrod to determine the proper length pushrod to be used. See our website under FAQ for detailed information on pushrod length.

    Titanium Valves:

    If you have upgraded to AFR Titanium valves in SB Chevy, SB Ford or BB Chevy applications they are coated with Chrome Nitrate (CrN) on the stem and seat area for longevity purposes. This is the same coating GM uses in the LS7 ZO6 applications and designed to last 50,000 plus miles. YOU CANNOT GRIND, REFACE OR LAP IN THE 45 DEGREE SEAT AREA. If you grind or lap in the valve, the coating is removed and the seating area on the valve seat will wear prematurely reducing the service life substantially.

    Guide Plates:

    ONLY USE THE ADJUSTABLE GUIDE PLATES SUPPLIED BY AIR FLOW RESEARCH! Pushrod guide plates are furnished with each set of AFR aluminum heads. Studs should be torqued to 55 ft./lbs. Silicon sealer is recommended on applications where the stud hole intersects the intake port. Pedestal mount heads do not require guide plates, part #’s 1472 & 1492,
    torque pedestal mount rockers to 25-30 ft./lbs.

LS1 Aluminum Cylinder Heads

  1. Installation Instructions

    ATTN: Please read through all instructions before attempting cylinder head installation.

    Warning: Piston dome to cylinder head clearance must be checked prior to final assembly of engine. Piston might need clearance with AFR Heart Shaped Chamber. Pay special attention to the outside edge of the valve to the inside edge of the valve relief in the piston.

    Valve Springs:

    It is the customer's respnsibility to check and make sure that spring pressures are correct for their cam.

    Valve Guide Clearance:

    Intake and exhaust guide clearance are .00125, on some severe applications with nitrous, marine, or blower usage looser guides might be required.

    Important:

    Compression ratio and piston to valve clearances must be checked before assembly. Part numbers 1610 through 1680-1 with the 2.080 intake valve usually will not fit a piston without valve notches having proper relief’s. Apply anti-seize to all bolts and spark plugs to ensure a long thread life.

    Coolant:

    It is important to maintain a 50/50 mix of antifreeze in the cooling system to prevent corrosion of aluminum heads. Don’t use tap water, use distilled water. Most supermarkets have purified or distilled water. Check labeling to verify purified through deionization.

    Torquing:

    We suggest NOT using a torque wrench on intake and exhaust manifold bolts. Just snug up hand tight with a wrench only.

    Valve Seats:

    Both intake and exhaust valve seats are heat-treated and compatible with unleaded fuels.

    Valve Tips:

    Do not grind your valve tips. Some AFR heads have hardened stellite tips which cannot be reground. If ground the tip will mushroom over causing severe damage. If your valve tips are magnetic you can grind a maximum of .015” from the tip.

    Accessories:

    Although AFR LS1 heads will accept OEM components; we highly recommend that premium aftermarket hardware be used with your new heads.

    Head Gaskets:

    With AFR 205cc heads use GM #12498543 or #12498544, or AFR #6846 head gaskets that are .040” thick. For AFR 225cc heads you must use a head gasket with minimum bore size of 4.135” such as AFR #6848 or Fel Pro #1041.

    Intake Gasket:

    Use factory o-ring style gasket or AFR #6830.

    Exhaust Gasket:

    Use GM stock replacement gasket.

    Valve Cover Gasket:

    Use factory style o-ring gasket.

    Head Bolts and Studs:

    High quality head bolts or studs with hardened washers must be used to prevent galling of the aluminum head. Recommended head bolts are ARP #134-3609, for head studs use ARP #234-4316. For maximum gasket clamping AFR recommends head stud kits. VERY IMPORTANT: You cannot re-use the factory LS1 head bolts. They are “torque to yield” design and can only be used once.

    Head Bolt Torque:

    Moly lube-oil mixture should be applied between fasteners, washers and area around head bolt to prevent galling and improper torque readings. Recommended torque values as follows: 11mm ARP, torque to 70 ft. Ibs with moly lube and 8mm ARP, torque to 23 ft. Ibs with moly lube. A re-torque is recommended after the initial start-up and complete cool-down (allow 2-3 hours for cooling). Sealer should be applied to all thread areas that enter into the block water jacketing system. Permatex is a good general purpose sealer.

    Spark Plugs:

    Use A/C #41-985 Platinum spark plug as a starting heat range. Plug selection is dictated by many factors including rpm level, compression ratio and type of fuel. Forced induction or nitrous applications usually required 1 to 2 heat ranges colder such as Autolite #3924. Spark plug gap should be determined by the ignition manufacturer. You can cross reference to your favorite brand if desired.

    Pushrod Length:

    This seems like an easily answered question, however, there are many variables. Block and cylinder head deck heights, head gasket thickness, varying cams, rockers arms, and valve length can all affect pushrod length. Please see our following best estimates: for 165, 185 or 195cc standard or .100” long pushrods work in most cases. For 205 or 220cc typically .100” or .200” long pushrods will usually achieve proper geometry. For exact pushrod length we suggest using an adjustable pushrod to determine the proper length pushrod to be used. See our website under FAQ for detailed information on pushrod length.

    Titanium Valves:

    If you have upgraded to AFR Titanium valves in SB Chevy, SB Ford or BB Chevy applications they are coated with Chrome Nitrate (CrN) on the stem and seat area for longevity purposes. This is the same coating GM uses in the LS7 ZO6 applications and designed to last 50,000 plus miles. YOU CANNOT GRIND, REFACE OR LAP IN THE 45 DEGREE SEAT AREA. If you grind or lap in the valve, the coating is removed and the seating area on the valve seat will wear prematurely reducing the service life substantially.

    Cleaning:

    AFR thoroughly cleaned your heads prior to shipment. Your heads were washed in a water soluble chemical agitation tank and blown out with high pressure air 3 to 4 times before they were boxed. However during some machining operations chips are packed and wedged into the water jacketing and occasionally come loose in transit. Keep in mind one chip the size of a dime breaks into hundreds of tiny chips and makes the situation appear much worse than it is in reality. It is not unusual if you blow high pressure air into the water jacketing to see additional foreign debris, or chips finding their way out. AFR recommends that you thoroughly blow out your heads prior to installation.

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