First of all you must make sure you have a piston from another p/s set that is the same as what you are rematching to. You can't take a novarossi piston and put it in an OS engine or whatever ( btw that would never work and was thrown out ther just for example
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I rematch from novarossi , almost all the pistons are the same aside from a few engines that have different bore/stroke ratios . If done properly this method yields the perfect p/s set , trust me .
I am in no way telling you guys to go out and rematch until your hearts content but never be afraid to try something if you think its logical .