ok so heres the deal i was told that in my 4g64 i can run 63 pistons since they are almost i dentical other than it being stroked and "slightly" bored from the factory. i want to change mine since they are known to be verry weak and prone to breakage since there skirt isso thin compaired to the 4g63 pistons whos skirt is nice and wide.

But whati need is your advice on what piston bore i should choose. since the 4G64 has aslightly larger bore (4G63 is 3.347" (85.0mm), 4G64 is 3.4055"(86.5mm) what would be your sugestions? i dont know how much over bor pistons i need for the 4g63 to match the pistons in my 4g64

 

You have a 4G64???

 

yes i do i have the 4g64 and i need to know what bore 4g63 pstons will work with my bore

 

No they wont i believe.

You need to look for pistons for a 3g GS or something

 

i believe they will and have talke to many who say they will butwhat they say is itwill work since the pins are the same diamiter and every thing is identical from piston to piston theonly diff is the length of the skirt.and they say that i just need a 2g 4g63 piston in the right bore hence the i need to know what bore i need since i havent orderd forged pistons.the factory bore specs between motors goes the 4G63 is 3.347" (85.0mm) and the4G64 is 3.4055"(86.5mm)

 

If you could find 4g63 pistons that are .30 over and have your engine bored to match than the only thing I would make sure is that the wrist pin on the piston is the exact same distance from the top of the piston or expect a change in compression ratio, but otherwise...
4G63 is "3.347 (85.0mm), 4G64 is 3.4055(86.5mm" pretty much sounds like you would have to find a set of .10 over rings