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