Test 1. The first version of the 572 seen here on the dyno with the AFR 335 heads, Edelbrock Victor Jr. intake, custom-built Quick Fuel Technologies 950cfm carb, Petronix Flame Thrower billet distributor and a cam with 248 degrees/258 degrees duration (at .050) and .613-inch valve lift (intake and exhaust) was actually the best of the six different combos tested. Maximum torque was 730 at 5,100 rpm while the maximum horsepower was 748 at 6,000 rpm. Not content to leave well enough alone, more swaps and testing were done just to see what they would do.
Test 2: The second test version of the engine consisted of the same AFR 335 cylinder heads and same cam. What changed was the swapping out of the Quick Fuel 950cfm carb for that of a Quick Fuel 1050cfm carb and the Victor Jr. intake was exchanged for that of the Dart 4500 series intake.
This second combination yielded nearly the same results as the first combo. The maximum torque was 736 at 4,800 rpm and the maximum horsepower was 747 at 5,800.
Test 3: This test mule version is very much like the first build. This time around Ben Smeding had a theory and wanted to test it. Ben had taken a set of the AFR 335 heads and reshaped each combustion chamber wall nearest the intake valve. The hope was to take advantage of the reground 52 degree valves at maximum lift.
So off came the old heads and on went the experimental cylinder heads. The Victor Jr. intake was put back on as well as the Quick Fuel 950cfm carburetor and the same cam was used. Maximum torque was 688 at 4,500rpm while maximum horsepower was 673 at 5,500rpm. So much for that theory and those reshaped combustion chambers. It was back to the drawing board.
Test 4: Version number four was similar in every way to the very first configuration except for the Dart intake manifold and a custom-built 1050cfm carburetor that Bill Jenkins had brought out with him. The maximum torque was 736 at 4,700 rpm and the horsepower 726 at 6,000rpm. Definitely a step in the right direction compared to the previous test, but still not as good as the first version.