Alright I'm going to flycut my pistons but the dummy heads that they send me are 241 heads. Well the heads I'm going with are the PRC 2.5 5.3l heads. Well I was thinking the 241 heads are a lil' taller aren't they than the 5.3l heads? So if I cut .080 and .100 with 241's and I slap on the 5.3L's the gap would be tighter?

 

You just need to figure out how much you're taking out of the piston itself.

 

put the piston to be flycut at TDC, put the dummy head with the cutter in it on the block and let the cutter slide down the guide till its on the piston. measure .080-.100 up on the cutter stem starting from the point its coming out of the guide and set the stop at that point. so when you cut into the piston the stop will stop you at your desired depth. get it? doesnt matter the casting # of the dummy head.

did you read this