I just picked up a freshly built motor from a buddy and I decided to do the compression math and noticed an odd thing about the numbers stamped on the Wiseco pistons. The catalog has the part number listed as K541M815 but the pistons are stamped 6541M815. I assume since the 541M815 part is the same, I have the 8.3-8.6 range of their pistons.

Anyone know why my piston is stamped 6 and the catalog starts with K? Was this something new? I know these pistons were purchased probably 1-1.5 years ago. Maybe they recently changed their part numbers?

Thanks for the help!

 

6541M815 - ACURA TURBO -12cc 1.181 X 81.5MM $173.43