Two things come into my mind on piston rings, thickness of the face and the tension. I'm almost positive that all the new cars have thinner piston rings than before, 5/16 inch face old days, 1.5 MM or 1.0 MM rings now The last stroker motor I built for myself has 1.5 MM top and 2nd MM rings with a 3.0 MM low tenison oil rings, no vacume pump or crankcase evac. system, two breathers on each valve cover I forgot to measure the rotational break away and rotataional torque but it is a bunch less than the other motors with 1/16,1/16, 3/16 standard oil tension ring set that I have built My next motor will have 1.0,1.0, 3.0 MM low tension rings with a vacume pump Let us know what you decide