[Happy_dan]

I am refreshing my 1968 C-20 327 4BBL automatic engine. I have it stripped down to block. The crank and heads are at machine shop.

I will be replacing main and rod bearings but hoping to keep the rods and pistons that are in it. They are in good shape and I don't want to buy pistons on top of everything else unless necessary.

I am planning in simply deglazing cylinder walls and hoping to replace rings only. It was using oil and dry and wet compression test revealed a couple of weak cylinders so I think it needs rings.

My question is, can I simply buy standard rings and replace them, or do I need to have cylinders bored and go .30 over?

I measured bores on an x and y axis in center middle and top and they range from 3.976 to 4.003. Most are 3.997 to 4 exactly.

I have searched for information but not sure on what to search for to find the limitations of standard rings and I know we have a lot of expertise here!