4.3 short block maximum bore

[saltlydawg]

I have a 1990 Mercruiser 4.3 which I have torn down and going that although the block looks fantastic, spinning two rod bearings trashed the crank. While at the machine shop I spied a rebuilt short block non balanced shaft just like mine, which they said would sell for $375. They even offered to install brass plug and my marine cam. Here enters my dilemma, although it has clevite bearings, and new pistons, the new bore is .60 over. Is that a bit much considering the duty cycle a marine engine endures? Like I said my block is great and is still mics out at an even 4" so I would end up at .30 over. Honestly a short block sounds attractive, but I would like a seasoned opinion.

Thank you all in advance for your time.

 

[Bondo]

Re: 4.3 short block maximum bore

Ayuh,... While .030 over is Great, 'n .060 over is the Max,...

$375. sounds like a bet I'd probably take...

 

[saltlydawg]

Re: 4.3 short block maximum bore

That includes me giving up the core, still a good deal? Right now it makes a wonderful centerpiece in my garage. Seriously though is there anymore value in the block with the merc tag and casting number? I am thinking $375 for the short block would really reduce the burden of getting this beast back in the water. Thanks for your expert opinion!

 

[Don S]

Re: 4.3 short block maximum bore

Mercruiser, OMC (when they were in buisness) and Volvo do not recommend or even sell parts for anything over .030 over.
All the popular rebuild houses that sell cheap long blocks, automatically bore to .060 because they do not have to measure anything.
If it doesn't clean up it's junked. One size fits all and little effort and skill is needed to assemble.