L98 block over bore max?

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Dec 21, 2003 | 09:49 PM

Formula 94 LT1

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L98 block over bore max?

I saw lingenfelter made an "L98" with Afr heads and super ram intake, but was unsure if the block actually was originally an L98 block because the bore was 4.155".... they apparently overbored the lt1 block .100" so maybe the L98 block was a little thicker??

Dec 21, 2003 | 09:57 PM

CORKVETTE1

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Re: L98 block over bore max? (Formula 94 LT1)

it was a bowtie 400 base block :cheers:

Dec 21, 2003 | 11:02 PM

vader86

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Re: L98 block over bore max? (Formula 94 LT1)

I dont know if youre allowed to bore the stock 350 block more than .060"

Dec 22, 2003 | 01:56 AM

mistaben

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Re: L98 block over bore max? (vader86)

can you have heating problems at .040? or when do they begin in reality?

Dec 22, 2003 | 01:22 PM

CFI-EFI

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Re: L98 block over bore max? (mistaben)

Quote:

can you have heating problems at .040? or when do they begin in reality?

It varies from block to block. When the block is cast, the cylinders are located by a sand core. "Core shift" can result in different cylinder wall thickness. The block can be "sonic tested" for wall thickness. I wouldn't be comfortable with a bore of more than .030" over in a performance application without sonic testing first. 350 pistons ARE readily available in .080 over. Good luck, and...

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Dec 22, 2003 | 10:58 PM

kcl98

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Re: L98 block over bore max? (mistaben)

I've got a .040 over L98 in my Camaro that's running just fine - 68,000 miles on the re-build & running high 12s. .060 might be iffy, but I think .040 is fine.

KC

Dec 23, 2003 | 01:47 PM

CFI-EFI

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Re: L98 block over bore max? (kcl98)

A .040" overbore is probably "safe", 98% of the time. Even .060" is safe 90% of the time. I would just hate to be the guy to spend the time and money, and find out the hard way, that my block was the exception to the rule. Good luck, and...

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Dec 24, 2003 | 05:54 PM

JAKE

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Re: L98 block over bore max? (Formula 94 LT1)

When considering going more than .030 over, have the block sonic checked. You'll want the thickness to be there on the thrust walls.

I've had BBs crack at the bottom of one bore on only a .060 over-bore. Blocks are different, some can take it , some can't.

Jake