JE/ SRP PISTON #140685 060 OVER CH 1.395 AND 070 OVER #140686 CC48 DOME this is the piston i used in the 526 .6.535 rod. OR #139837 060 OVER CH 1.245 AND THEY MAKE THEM UP TO 100 OVER THIS PISTON WILL LET YOU USE THE 6.700 ROD THEY ARE HI CR PISTON BUT THERE BOTH SHELF PISTONS and they may make them in a small dome and flat top i did not look. you can do that just look them up on the web