big inch small blocks do run good, but build a bbc and you can always go biggger. start with a 540. Doesn't cost any more than a 509 and you can build bigger and bigger as time goes on! not to mention the extra hp and torque you'll have along the way!! i started with a 509 then went 548 now almost finished with the 632! No way is a sb gonna catch my 632!
If your like me you'll always want more hp/ tq so start as big as you can and it WILL SAVE U $ IN THE LONG RUN!!