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CHEVY HIGH PERFORMANCE
FLOW FIGURE "SPREADSHEET"

NOTE: All flow figures were obtained using a 4.250" bore fixture and exhaust figures were compiled using an Amduri 2.25" test pipe. All information was recorded using the same Superflow 600 flowbench and fixtures. (All of this info can be downloaded off of the Chevy High Performance magazine website @ www.chevyhiperformance.com . )

Cylinder Heads used for testing are as follows:

#1 Canfield 305 #9 Dart Pro 1 (325 cc)
#2 World Products Merlin VR (Cast Iron) #10 Edelbrock Performer RPM
#3 World Products Merlin (Aluminum) #11 Brodix -2X
#4 Holley Avenger #12 Brodix -4
#5 GM 188 (Cast Iron) #13 Dart Pro 1 (345 cc)
#6 GM 990 (Cast Iron) #14 Brodix -3
#7 Brodix -2Plus #15 Edelbrock Victor 7760
#8 GM Performance Parts 401 #16 Edelbrock Victor (CNC Port)

Cyl. Head AFR 315 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
CC's 315 305 310 310 314 317 318 318 322 325 325 345 345 345 370 370 375
0.100
76
75 79 73 72 68 69 72 70 76 73 72 76 79 80 71 78
0.200 162 161 158 144 137 129 125 150 143 141 146 134 149 141 139 145 146
0.300 232 215 216 217 199 188 183 207 200 200 204 185 210 199 195 207 211
0.400 282 257 258 269 251 233 233 252 236 251 248 232 260 254 245 254 264
0.500 321 303 292 289 292 259 264 287 275 293 282 277 299 292 293 290 307
0.600 348 328 313 296 315 291 292 318 310 325 300 314 328 323 333 322 338
0.700 368 339 325 305 330 313 - 337 330 345 318 340 351 350 360 342 354
0.800 370 332 327 312 340 - - 336 340 355 319 360 352 365 366 356
Avg. Flow 298 276 270 262 266 247 240 270 262 273 260 263 278 275 276 272 293
                                   
                                   
Cyl. Head AFR 315 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
CC's 315 305 310 310 314 317 318 318 322 325 325 345 345 345 370 370 375
0.100 62 61 57 66 60 45 53 55 53 58 58 57 66 59 56 57 58
0.200 133 115 100 129 122 90 103 111 116 95 116 93 127 108 83 115 122
0.300 199 163 141 173 171 131 140 139 142 140 144 133 163 142 118 143 190
0.400 256 199 175 195 207 170 176 174 179 180 175 165 192 183 150 180 230
0.500 284 228 193 207 233 188 198 201 204 215 203 193 222 216 188 208 266
0.600 290 251 207 214 252 195 204 225 227 238 226 222 244 241 216 230 282
0.700 293 265 213 214 264 200 207 240 244 255 244 240 256 256 230 246 287
0.800 300 273 222 214 269 202 207 252 259 273 259 252 263 273 245 259 287
Avg. Flow 251 213 179 192 217 168 176 192 195 199 195 185 210 203 176 197 238
                                   
Avg. I/E Ratio
84%
77%
66%
73%
82%
68%
73%
71%
74%
73%
75%
70%
76%
74%
64%
72%
81%

NOTE:

AFR 315cc exhaust flow figures were obtained using the optional tulip valve that comes standard on the AFR 335 and 357 cc packages. The standard valve that comes with the 315cc package would flow approximately 10 CFM less (Refer to our website or latest catalogue for exact flow figures.) AFR feels 84% is actually too high an intake/exhaust ratio for a normally aspirated engine and utilized the different exhaust valve to bring the ratio down to 81%.

IMPORTANT:

Many of the competitor's cyilnder heads advertised in this testing have MUCH LARGER intake runner volumes. Keep that in mind when evaluating the flow figures advertised. AFR also offers larger intake runner volumes that will be tested shortly. (Refer to our website or our latest catalogue for accurate flow figures on the entire Big Block product line we offer.)

VERY IMPORTANT:

All flow figures taken in this test were recorded using a 4.250 bore fixture. Current chamber designs and valve sizes used today (typically 2.250 - 2.350 for BBC intake valves) would show better results being tested on the larger 4.500 bore fixture. (Primarily due to unshrouding the valve with the larger bore size.) With so many production GM blocks, as well as the aftermarket, starting at 4.500 inches in bore size, we feel this is much more representative of the current trend in Big Block Chevy engine building. All published flow figures from AFR were obtained using a 4.500 bore fixture. However, the fact that all the information obtained at Westech was recorded using the same bore size (4.250), the same flowbench, the same operator, etc., this still proves to be a valid test and comparison, eliminating many variables that could potentially exist evaluating and comparing flow data.

 

The following information was recorded the same day at Westech, flowing the exact same AFR 315cc intake port, simply swapping test fixtures to the larger 4.500. These flow figures are almost identical to the published figures from AFR. They are as follows:

LIFT
.100
.200
.300
.400
.500
.600
.700
.800
CFM (Intake)
79
170
253
315
350
375
386
390
CFM (Exhaust
67
135
198
255
290
302
314
323
(Note: w/ optional valve)

 



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