1970 Z/28 Pistons-Replacements?


Veteran Member
Lifetime Gold Member
Sep 15, 1999
Ontario, Canada
I would see if a hone at .040 would clean it up enough rather that going to .060. You don’t want thin walls.


Veteran Member
Oct 9, 2020
Bad thing is the guy I bought the block from had it bored 40 over. So I guess I'm going to 60. Main reason I bought the block was the fact that it was align bored,decked and cylinders bored and CLEAN.
two common piston forging alloys are 2816 and 4032. Typically, 2618 are set up with considerably more skirt clearance than are 4032 --- because 2618 swells more than does 4032.

40+ is a common oversize. Most auto piston lines' shelf stock skips 10+ & 50+. However, some lines do include 45+, 50+, 55+ shelf stock.

If, IF you need 40+, you'll find it.

Also, it may've already been said, but with today's (tomorrow ?) pump gas, you'll likely be served best by avoiding dome pistons