My vote is for the 440. You can't argue with inches. Measure how far in the hole the pistons are and get cam spec'd for what you are doing. Sd or performer intake. I had a 440 that had pistons .074 in the hole steel head gaskets 906 heads 91cc checked. The old 509 cam,Team G intake[junk] 3800 convertor 3.91 in an Abody it ran 11.91 @111. So you can make power with low compression. There are a couple good reads on for A bodies only by IQ 52 about some low compression dyno testing he did.