Reading all your facts I would say a 1 sec gain is possible with your new combo, going from 78cc heads to 60cc could raise your comp by just over 1 point. The 3.91's and your 3500 stall will be weak though, I would up that to at least 4.30>4.56's and 28>29" tyres if you can fit them with a min 4500+ verter then it should really take off....but it'll no longer be a street/strip car if thats what it is now as most are.......just some thoughts.
I went from running 13.3@101 with a 3500 stall, .484" hyd., 750DP, small hdrs, with a stock '71 340, 3.55's/26" slicks to>
12.39@108, same block/heads but added an MP .590"sft cam, strip Dom int. 850DP, race hdrs., 4.30's/4200stall/28" slicks....3550lbs Cuda....and I only added 67hp to the motor with cam/carb/intake/hdrs which isn't a 1 sec gain in ET.
