If it was 450 HP with stock un-ported manifolds then it would be 467 with ported stock manifolds and 486 with long tube headers. Let's see if Thumper agrees.
Thanks man. I don't drink descent in math. Old eyes not looking at what I'm typing or brain fart. lol
Gary's numbers track almost identically with a motor I had built a few years ago with a mild 227/238 cam, aluminum heads and ported stock manifolds. Horsepower with full length headers on that one was 486.
Not sure, either ported iron or headers,but I'm not sure what will fit a early 60s best. I'm doing a 482 for a guy with a 64 and he's going to use ported iron. so we'll see how those fit in January.