cm644

Hi i have a 1987 still has sd and im looking into hci combos. the only thing the car has is headers and exhaust.so prettymuch stock. im wonderign with stock bottom end and pistons im looking to get between 350-400 hp. i have 2000 and i will convert to maf. Does this sound feesable and i was wondering if anyone has any combos in mind for my price that will get me where im looking to be. and whats the largest heads i can get with stock pistons. Thanks all.