wgreenlee4

Hey guys could someone help me determine which size rings go in my 302? I threw away the old ones months ago. Google was not as helpful as I thought, there is a lot of back and fourth. Also, my cylinders were ball honed (don't know what grit). The piston part number is E7ZE-OA. The block they came out of is from a 91 Thunderbird but I believe that part number is an 87 Mustang. There are metric sizes and english sizes available.

http://www.oreillyauto.com/site/c/se...1987&make=Ford

Also, could I use Moly rings with a ball hone? Everything is standard size, normal 4.000 inch bore.

Boss_Hotrod

I would say the OE pistons would use standard size rings. Beware though that if the pistons are worn and you put new rings on them they may not fit snug and run the risk of breaking or worse. Id suggest getting a set of rings and then checking the fit to the pistons (or better yet new pistons but they will have to be balanced to eack other and possibly rotating assembly to be perfect). Also you should be able to find a spec for a ring to piston gap. Be sure that is in spec or you'll run the risk of them bouncing and breaking. I think the OE manual has the spec in it but I don't have mine at the moment to check it.

wgreenlee4

Thanks for the advice. I actually sat down with a feeler gauge and measured the pistons, it was a hassle. They are in great shape. And the piston ring sizes ended up being metric (2-1.50MM, 1-4.00MM).