New to the mopar world,Need help with 318 build..pleeasse..

thanks,but i was thinking maybe i could use the stock pistons,and deck the block and such,and how much power are the stock pistons good for? Also it has late 70's-early 80's 360 heads on it now,i know of the low compression because of the heads,i was thinking also milling the heads some??and i need opinions on the thumper cam i like the sound,and i understand more for sound than perf.but is it any good really?,ive done that already,but thinking of swapping it for an extreme??im kinda pretty much broke,and the engine was running as of last week just tore it apart,to mill the heads,but need to know how much? Sorry for the long post,just got alot of question's regarding whats good,and what can be done better.how much are a good set of kb's(best bang for the buck)?