I would recommend studying the dyno-tested engine combinations at the website below. They should give you a good idea about combinations and the hp and torque different heads and camshafts will produce on 350's and 383's. Anything over 500 hp will probably not have good street manners. I built my 383 based on Combination #15. It is a great street engine, but I would not want a bigger cam with an automatic transmission.

www.ryanscarpage.50megs.com/