What's a good piston to use on the ford 2.3. Our rules say flat top valve relief and must be three ring pistons and weigh at least 510 grams with rings and wrist pin. Wrist pin must be stock outside diameter. I weighed the pistons I'm using and they're 570 grams. I think giving up 60 grams per piston is a lot. Also is there a difference in the small journal crank engines? I've heard some are better than others.