Engine Build Ideas...PLEASE HELP.

It all depends. the more HP, the more skill and $$ required. If the car is a 340, I would do the 340. A good rebuild with a decent hyper piston, good machining, a performance build will get you the 350hp level easy with basically stock stuff. A 360 needs nothing but the same hyper pistons and a cam to reach 360hp and that's not a big cam. The 450hp level gets more involved, both in ability and cash outlay. Costs for the lower output is about $12/hp, the higher figure will run about $15/hp.