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Old 01-09-2018, 10:16 PM   #1
oleguy
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Question Can I use a 350 Chevy that is bored .080 oversize?

I have a 350 CI. Chevy. engine, casting #3970010, that had under 20K miles on a so called (OVERHAUL when the truck was wrecked and totaled. It is bored .080 oversize. The cylinder walls show vary little ware. Otherwise engine checks out pretty good. I would like to hone the cylinders, re-ring the pistons, replace bearings etc. and use this engine, however I am of the opinion that .060 is pushing luck. I would like the opinion of the experts on this forum. THANKS in advance. Monty
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Old 01-09-2018, 11:07 PM   #2
truckster
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Re: Can I use a 350 Chevy that is bored .080 oversize?

I wouldn't do it without sonic testing. I'm even leery of .060 blocks.
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Old 01-09-2018, 11:46 PM   #3
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Re: Can I use a 350 Chevy that is bored .080 oversize?

I'm no expert but if it were me I would just save up the $1,200 for a new crate motor.

The cylinder walls get pretty thin even at 60 thou over and just a tiny crack in one cylinder will pressurize your cooling system with 100 psi compression. Lots of smoke would then proceed out of the freeze plug seams even though the motor might run on the other seven cylinders.

If the motor had absolute and severe sentimental value the only hope would be installing cylinder sleeves in all eight bores; but last time I looked those are at least $150 each so times eight that would be $1,200 and a lot of skill and iffyness to install required in my opinion.
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Old 01-09-2018, 11:50 PM   #4
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Re: Can I use a 350 Chevy that is bored .080 oversize?

I agree with the Truckster But if you KNOW for sure this engine ran fine with no overheating issues I would say go for it. But realize it won't take the abuse a .030 engine would and drive it accordingly. But with only 20k on it and you trust it, why bother with new rings, honeing and bearings? There is at least another 80k left in the engine. The most I would do is a new rear main seal after I checked the bearings. Just run it the way it is and save your money for other truck stuff.
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Old 01-10-2018, 12:43 AM   #5
truckster
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Re: Can I use a 350 Chevy that is bored .080 oversize?

I don't know any good machinist who would bore a SBC block to .080 over. The reason I say that is that you have to consider a question: If they were willing to go that thin on the cylinder walls, what else did they do to that motor?
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Old 01-10-2018, 12:46 AM   #6
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Re: Can I use a 350 Chevy that is bored .080 oversize?

NO.
It's not common practice for a reason, save your money and do it right.
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Old 01-10-2018, 12:57 AM   #7
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Re: Can I use a 350 Chevy that is bored .080 oversize?

Quote:
Originally Posted by truckster View Post
I don't know any good machinist who would bore a SBC block to .080 over. The reason I say that is that you have to consider a question: If they were willing to go that thin on the cylinder walls, what else did they do to that motor?
I build engines for a living and I was thinking the same thing. At .80 I’d be willing to be it runs hot more often than not.. I wouldn’t throw any extra money at it that’s for sure.
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Old 01-10-2018, 01:21 AM   #8
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Re: Can I use a 350 Chevy that is bored .080 oversize?

I have ran an 80 over 350 as a race engine, but only for a short time. No overheat problem but it was only a matter of time till it let go.
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Old 01-10-2018, 01:38 AM   #9
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Re: Can I use a 350 Chevy that is bored .080 oversize?

it's very common for a rebuilder to go .060 but .080 is pushing it. Stock build would probably be ok if the walls sonic check but I wouldn't base a performance motor off of that block...
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Old 01-13-2018, 11:15 PM   #10
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Re: Can I use a 350 Chevy that is bored .080 oversize?

Thanks guys for the input, you verified what I already knew but did not want to admit. The engine is toast and will not be used.
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