they are Wisecos, stamping on top of pistons says:
6596M86
2684L

they are stroker pistons but can't find in any catalog what compression ratio are these
any help would be great

 

if they are off the shelf pistons a quick google search of the part # should tell you. if not you could always call them yourself. and if that fails... google CR calculator and it should give you a formula to get the CR. you will most likely need a machinist micrometer and other tools to get exact measurements of the things you need to plug into the formula, but it can be done. more than likely no one will be able to tell you the CR on here from part #'s

 

If you post a picture of the top of the piston we can give you a good idea.

 

^
will post later when I get to my laptop


p.s. google search didn't gave anything significant

 

here


image hosting

 

not that this is conclusive in any way shape or form

but that dish looks similar to the stroker pistons i had at one point...if its -12cc it will be 8.5:1 in the DSM head and 9.0:1 in the later Evo head

 

nm

 

emailed Wiseco, no reply so far..

 

that will take a few days. Calling them would get you your answer quicker