i just bought a set of used pistons the guy did not know much about them as far as he knows thay are for a 350 chevy forged pistons,i can not find anything on these pistons to find out what i can use them in numers i founed inside of the pistons are 3850139 or could be 3850'39 the second number under it is 098-99 any help on these pistons would be very greatful thanks take care