'cuz it is just easier.... no need to compress the rings! Ideally, you would accurately measure the rod length and the piston CH that you are using for deck measurements for best accuracy. Piston CH is easy when assembled wiht a pressed pin; rod length is a bit tricker. Otherwise, you just have to go on faith that your rod length is actually 6.123"..... probably so from the factory, but a reman rod can be short.
