C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Head volume and Compression

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Old Aug 30, 2007 | 09:39 AM
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Default Head volume and Compression

Quick question simple answer.

1990 L98. What is the compression? Is it 10:1 or 10.5:1?

What is the head volume? 58 or 60CC?
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Old Aug 30, 2007 | 09:55 AM
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10.25:1

They tinkered with pistons alot in the L98 years, messing with the final CR.

Head chamber spec is 58cc for all '113, though people who have actually had it measured have come back with different results (sometimes 56cc, sometimes 60), so there seems to be more build variance in the '113 head.
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Old Aug 30, 2007 | 10:00 AM
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I believe L98's maxed out at 9.5:1.
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Old Aug 30, 2007 | 10:05 AM
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I'm looking at heads that are 62-64 ccs.

I'll lose about a point of compression by my estimations.

What do you think?
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Old Aug 30, 2007 | 10:28 AM
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Originally Posted by vader86
10.25:1
1990 L98 9.5:1
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Old Aug 30, 2007 | 11:35 AM
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Originally Posted by InHot
1990 L98 9.5:1
Incorrect.

It is 10.25:1
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Old Aug 30, 2007 | 11:48 AM
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Originally Posted by vader86
Incorrect.

It is 10.25:1

When I removed stock pistons on my 90, the pistons were Mhale Flat top.

No dished as previous years.
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Old Aug 30, 2007 | 04:48 PM
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guess I'm going with 10.25:1
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Old Aug 30, 2007 | 05:01 PM
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Then it is 9.5:1 on an '89?
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Old Aug 30, 2007 | 05:10 PM
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Originally Posted by dan0617
Then it is 9.5:1 on an '89?
Yes, it is 9.5:1 on 1989. 1989 have dished pistons. All 113 heads are listed as 58cc. I don't like losing compression if avoidable. Can they shave the heads a bit?
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Old Aug 30, 2007 | 05:21 PM
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Originally Posted by BADDUCK
Yes, it is 9.5:1 on 1989. 1989 have dished pistons. All 113 heads are listed as 58cc. I don't like losing compression if avoidable. Can they shave the heads a bit?
There could be an upside. I may supercharge the car, so 9.5 wouldn't be a bad place to be....ya know, while I'm at it....
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Old Aug 30, 2007 | 05:33 PM
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Originally Posted by jsup
There could be an upside. I may supercharge the car, so 9.5 wouldn't be a bad place to be....ya know, while I'm at it....
Yeah, and that would allow you to run cheaper gas eventually paying for what is turning into a $10,000 upgrade!
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Old Aug 30, 2007 | 05:35 PM
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Originally Posted by BADDUCK
Yeah, and that would allow you to run cheaper gas eventually paying for what is turning into a $10,000 upgrade!
Serious....
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