How far do you want to go?
Whats your skill level?
331 stroker, 347 stroker 393 stroker up from there it depends on how much fab work you want to do. There are guys running 500 cubes in the foxes on race night .
If you get up to 400 hp on the stock drive train youll be good, after that you will need to look into a better trans.
More power also requires a better method of putting it to the street. Tires, suspension frame rails. The list of mods quite long my friend