i built a 500"-400 for some friends to bracket race. it has an eagle crank, bill miller alum rods, and je pistons. the rods required some healthy notches at the bottom of the cylinders. the short pistons hang out the bottom of the bores some. short pistons should run tighter clearances to keep them stable. i don't think that "short piston" should necessaryily equate to "shorter life". a lot of high rpm endurance engines use very short pistons. i was concerned about a short piston hanging to far out the bottom of the bore and becoming unstable. so far the engine has held together and been pretty reliable.