420 pistons in a 40 block?

[TractorNutt]

I have a 40 that needs an overhaul. It has std. 4" pistons. I have a nice set of 420 pistons which are 4.25". Can my 40 block take a bore up to those 420 pistons? Any comments or experience appreciated.

 

[Mike M]

I know someone who did that. I never liked the idea though. I'd rather go to the next oversize just enough to clean it up. This way you can go more again later if ever needed.

That's alot of metal to remove and always a chance of hitting a thin spot ? Plus the 420 used a water pump so I don't know if you will end up with a cooling problem or not ? The fellow I know who did it ended up not running his much afterwards. I have no idea if he had any problems or not.

 

[TractorNutt]

Thanks, I think I will just get new pistons for the 40 and bore it oversize and forget about the free 420 pistons I got...