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

'85 engine spec - compression ratio.

Old Mar 16, 2022 | 01:04 PM
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Default '85 engine spec - compression ratio.

Trying to figure out what gasket thickness to use with 64cc heads on the '85 engine. My understanding is the pistons are forged flat tops, but when I search specs I get all sorts of numbers.

Does anyone know what the piston clearance cc is for the flat tops?

This is what I got so far:



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Old Mar 16, 2022 | 05:38 PM
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It should be close, try this:

Bore (Inches) 4.000
Stroke (Inches) 3.480
Connecting Rod Length (Inches) 5.7
Cylinder Head Volume (cc) 64
Deck Height (Inches) 0.025
Head Gasket Bore (Inches) 4.166
Head Gasket Thickness (Inches) 0.039 (FelPro 1010)
Piston to Cylinder Wall Clearance (Inches) 0.003
Top Ring Land Height (Inches) 0.25
Piston valve relief cuts (cc) 6

Few good resources of course as you've seen for static CR
https://diamondracing.net/p-10-compr...alculator.html

Then there are dynamic CR
https://thedynoguy.com/compression-calculator
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Old Mar 16, 2022 | 05:43 PM
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Stock CR is advertised as 9.0 for the 85
Deck clearance spec is 0.025 or 0.020
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