Visual Aid For Figuring Custom Pistons??

I'm not sure what you're asking. but I know that when we went to alky with our dirt motors diamond had us take a plaster paris mold of the head the way we were going to run it.along with the cam species along with the bore and stroke of the motor.they sent us the prettiest pistons you ever wanted to see.and in the motor came out to 15 to1. the only trouble with that we had to buy 3 sets to get them. and with a custom piston they are 10 to a set or at least they used to.we bought 4 sets.and man what a motor you could hear that thing over any thing on the track and at 7500 would put chills down your back.and talk about SOB to start on a cool damp night.I would drain the front fuel bowl and fill it with gas and wen it would go from gas to alky you could here it change like a top fuel motor..oodamit boy.hope this is a help......Artie