Forged pistons for 4.1's are pretty uncommon because they have to custom made. New a set goes for around $750-800. Many guys have run the Speed Pro hyper pistons with good luck well into the 10's and they are pretty cheap and easy to find. I have a set of used Speed Pro hyper turbo pistons that are .030 over for a 4.1 that I would sell for $100 with a set of turbo rods attached to them. They came out of a N/A motor that I bought out of a Toyota 4X4. I am sure the N/A 4.1 worked real well with 8.5 compression!