Compression Ratio Guess?

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Jan 27, 2009 | 01:04 PM

Dave64

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Drifting

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From: Avondale Arizona

2024 Corvette of the Year Finalist - Modified

2023 C2 of the Year Winner - Modified

2022 C2 of the Year Finalist - Unmodified

2021 C8 of the Year Finalist - Unmodified

2019 C2 of Year Finalist (appearance mods)

St. Jude Donor '19-'20-'21

Compression Ratio Guess?

Before I go any further, I wonder if anyone could venture a guess as to what CR I may have here:

327 bored 0.040" over
Block height 9.005"
Crower Sportsman Rods 5.7"
TRW Flat-top Pistons #L2165F
Edelbrock Performer RPM Heads #60899 64cc
Head Gaskets FelPro #7733PT2 0.039"

My goal is 10:1. Is this in the ball park? Thanks for any positive input.

Dave

Jan 28, 2009 | 05:08 PM

Dave64

Thread Starter

Drifting

Joined: Jul 2005

Posts: 1,755

Likes: 710

From: Avondale Arizona

2024 Corvette of the Year Finalist - Modified

2023 C2 of the Year Winner - Modified

2022 C2 of the Year Finalist - Unmodified

2021 C8 of the Year Finalist - Unmodified

2019 C2 of Year Finalist (appearance mods)

St. Jude Donor '19-'20-'21

ttt

Jan 28, 2009 | 07:56 PM

leadfoot2

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From: Tucson Ariz

Assuming orig bore and stroke was 4" x 3.25" and there are no valve reliefs in the pistons and the top of them are even with the deck you have about 10.4:1.

Jan 29, 2009 | 10:04 AM

Dave64

Thread Starter

Drifting

Joined: Jul 2005

Posts: 1,755

Likes: 710

From: Avondale Arizona

2024 Corvette of the Year Finalist - Modified

2023 C2 of the Year Winner - Modified

2022 C2 of the Year Finalist - Unmodified

2021 C8 of the Year Finalist - Unmodified

2019 C2 of Year Finalist (appearance mods)

St. Jude Donor '19-'20-'21

Thanks Leadfoot. I guess I'm int the ballpark as planned. Take care.

Dave

Jan 31, 2009 | 09:00 AM

64_365

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From: Dover AR

Pi r square, cornbread are round.

Feb 2, 2009 | 01:37 AM

Cris

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Joined: Oct 2000

Posts: 491

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From: Los Altos Hills, CA

Dave:

No reason to guess at your compression ratio. If you aren't handy with math there are several on-line compression-ratio calculators. Here's a link to one of them:

http://www.csgnetwork.com/compcalc.html

After a quick search I found your TRW L2165F pistons have a pin height of 1.671 inches. This leaves the piston (at top dead center) .009" inches below your deck of 9.005". The L2165F pistons also have valve reliefs that create an extra 5.4cc volume. The felpro gasket you are using has a bore of 4.125".

Plug that all into a calculator and you get a compression ration of 9.6:1

Feb 2, 2009 | 09:00 AM

lackomotorsportsllc

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From: Amherst Ohio

I agree with Cris

never guess always calculate.......numbers dont lie!

Feb 4, 2009 | 01:19 PM

Dave64

Thread Starter

Drifting

Joined: Jul 2005

Posts: 1,755

Likes: 710

From: Avondale Arizona

2024 Corvette of the Year Finalist - Modified

2023 C2 of the Year Winner - Modified

2022 C2 of the Year Finalist - Unmodified

2021 C8 of the Year Finalist - Unmodified

2019 C2 of Year Finalist (appearance mods)

St. Jude Donor '19-'20-'21

Thanks guys. I can live with 9.6. It's not 11.5 the motor is supposed to be, but it will be a driver that will accumulate many miles. I just hope the crisp sound is still there. I know it won't really be the same, but at least it will be solid lifter crisp. Thanks again.

Dave