snow-is-king

Working on a freinds 94 Arctic Cat 580 ZR EFI.

Melted a piston, and trying to keep the repair costs down. I found a 95 used cylinder and piston in really nice shape with only 400 miles on them. The problem is the intake on the 93-94 is 38mm, and the 95 and up is 40 mm. Any thoughts as to what effects that would have?

Thanks in advance.