you don't actually think it makes a hp difference on a 2 barrel stock application, do you?? that's just silly. 70-71-72 yeas are the same just a different casting number. personally I would ditch the 2 barrel and use a performer air gap intake and a 4 barrel holley 670 street avenger carb.
You are right Terry, the two barrels are out there. I have been looking for a 3916313, but the guys don't want to sell them or they want a leg and an arm for them. The same goes for the chevelle 3973467 (71). I found a 72, 6263752, which has the least horsepower of the three for a decent price. I will continue looking for the 313, or who knows, I just might go with a four barrel. Thanks Terry.
The lower HP rating for 1972 Chevys was due to a change in the method used for rating HP; and was not a reduction in the hp the engines produced.
'55, '56, '57 Nomads North Alabama area Gary