that's the thing with those blank pistons, you have to experiment to find out what works best for you. a lot of people like to wrench on about every part on their cars. just try something small and 2 regular sized holes, as on a standard piston, and work with that.
i rarely see anyone using a third hole, much less the forth. what i see people doing is drilling one large and one small hole. in different variations/sizes.
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