Do I really save much?

I'd say check the prices of what it takes to make it a stroker vs. keeping it a 360 and rebuilding it. BTW: if you change pistons you should get it balanced.

As for the heads I agree with crackedback. The RHS heads are a great bargain. You'll spend almost as much getting old heads rebuilt with big valves and porting and they still won't perform like the RHS heads.