We have done alot of AD V8 conversions through the years and here is my experience: 3 3/4 bore(265 & almost 305)--no problem, 3 7/8 bore(283)--no problem up through 0.060 overbore, 4" bore(302,327,350)--no problem with stock bore and no a/c. This is with a radiator that is for sure in good shape. If one gets outside these parameters it can lead to heating problems and that means electric fan(s) or dual 1" tube aluminum radiator. Do not pay the street rod prices for the radiators, go to a circle track supplier, they now are stocking verticle flow radiators along with the crossflow for less than $200. You have to make your own mount but I can do that for a 250 to 350 bucks saving.
