Max overbore on a 303 Olds?

I think that covers it. I have one that I just dissassembled after years of sitting outside, block seems okay but I know it will take a fair amount to clean up the bores.

 

Those blocks were bored 3/16" over with no problems back in the old days ...

 

If you ever sonic checked one you would never bore one 3/16


.125 over or

3.875 to 324 bore size is max

Tony

 

I was just reading an old hot rod magazine last night and there was a dragster that had a blown 371 overbored 3/16 to 406 cubes. Were the cylinders thicker on those than the old 303's?


Don

 

If it was a dragster they might have cemented the block.

 

Cool, .125 is what I thought too, just wanted to confirm that. Thanks Tony.

 

In the time when 303s cost $25 at the junk yard. When you couldn't get a free one. We regularly went to 3 15/16. I had one. Never any problems. But your water jackets have had another 50 some years to rust. And the extra inches won't really be noticeable. Unless it's a race car.

 

The answer to this question is simple. Haul it down to your machinist, and have it sonic tested.

 

I probably won't even go .125 but I will if I have to. I'll only bore it enough to clean up the rust. This motor was seized, I'm not after cubic inches just want it cleaned up.

 

Call me
I can help you with pistons and rings...Pistons are easy in any bore size needed....The only thing we need to be careful of is ring selection(sizes and widths availablity)

Tony