When the smoke finally cleared from the dyno cell the results of the new heads were impressive to say the least. Even on this 400ci pump gas build, the engine picked up an average of 2 lb-ft in spite of the larger runner, a gain in peak power of 11 hp, and a whopping 26 hp at 7,500 rpm, which is close to the ideal shift point in both combinations. In fact, the 235 combo would likely need around 7,700 rpm for the best results. In short, the swap to the 235s showed no loss of bottom end whatsoever; increased the peak power noticably, moving it 600 rpms higher; and simply hung on to those gains to produce an extremly fat power curve; boosting the average high rpm horsepower numbers signifiantly. And true to their words, the 227 valvetrain transferred over with no issues whatsoever.

Our testing isn't complete by any means and the next time we present the 235s, we'll have our own combination together, showcasing what an all-out effort can produce-we have no doubt that we'll be tickling well over 725 horsepower. Until then, follow along as we unveil AFR's newest heavy hitter!

Quick Notes
What Is It
235cc small-block cylinder heads
What We Did
Check the gains over a set of AFR 227s
Price (APPROX)
$2,225 for the pair, $219 upcharge for titanium retainers

DYNO DETAILS
AFR 227
ADVANCE 37 degrees
JETS 98/98
MAX TORQUE 530 lb-ft @ 5,200 rpm
MAX POWER 610 hp @ 6,600 rpm
AVERAGE TORQUE 492 lb-ft
AVERAGE POWER 517 hp
POWER 1.53 hp/ci
AFR 235
ADVANCE 34 degrees
JETS 96/98
MAX TORQUE 529 lb-ft @ 5,300 rpm
MAX POWER 621 hp @ 7,100 rpm
AVERAGE TORQUE 494 lb-ft
AVERAGE POWER 517 hp
POWER 1.55 hp/ci

BUMPSTICK
MANUFACTURER Isky Racing Cams
TYPE Solid-roller
DURATION AT 0.020 302/306 degrees, intake/exhaust
DURATION AT 0.050 268/272 degrees, intake/exhaust
VALVE LIFT 0.705/0.705-inch intake/exhaust (1.65:1 rockers)
LASH 0.028/0.028 inch, intake/exhaust
NET LIFT 0.677 inch
LOBE SEPARATION 106, installed at 105 ICL

FLOW SPECS
227CC COMPETITION
LIFT INTAKE CFM EXHAUST CFM
0.200 153 120
0.300 214 167
0.400 265 214
0.500 297 230
0.550 308 234
0.600 314 238
0.650 318 241
0.700 321 243
*17/8-inch pipe on a 4.125-inch bore

235CC COMPETITION
LIFT INTAKE CFM EXHAUST CFM
0.200 159 120
0.300 221 175
0.400 270 214
0.500 305 235
0.550 316 242
0.600 324 247
0.650 330 251
0.700 334 254
0.750 337 255
0.800 340 256
*17/8-inch pipe on a 4.125-inch bore

SOURCE
T&D Machine Products
Carson City
NV
775-884-2292
www.tdmach.com
Dart Machinery
353 Oliver Street
Troy
MI  48084
248-362-1188
http://www.dartheads.com
Fel-Pro/Federal Mogul
Detroit
MI
800-560-1400
www.federalmogul.com
Holley Performance Products/Brands
1801 Russellville Rd.
Bowling Green
KY  42101
270-781-9741
www.holley.com
Air Flow Research
28611 W. Industry Drive
Valencia
CA  91355
661-257-8124
www.airflowresearch.com