Question About Compression and Head Gasket !
Thread Starter
Race Director
Joined: Aug 2006
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From: D / FW
Question About Compression and Head Gasket !
I have a 383 LT 4 with ported Stock Heads and JE dished Blower pistons.
No boost now but It will get 8 lb's from D 1 later.
It has 9.8.1 compression with .29 head gaskets .
What compression loss could I expect with .40 gaskets.
I either need to boost [ don't want to blow gaskets either ] or do a piston change and get compression up to 11.1.
Rather boost but worried about too much compression.
What should be the max compression you would want on a street/strip aluminum headed engine on 8 lb's boost.
No boost now but It will get 8 lb's from D 1 later.
It has 9.8.1 compression with .29 head gaskets .
What compression loss could I expect with .40 gaskets.
I either need to boost [ don't want to blow gaskets either ] or do a piston change and get compression up to 11.1.
Rather boost but worried about too much compression.
What should be the max compression you would want on a street/strip aluminum headed engine on 8 lb's boost.
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Just find an online compression calc program and plug in the piston to deck, negative piston cc, chamber cc, head gasket size.
Since 95% of the time blower motors are not running on boost you need some compression. Again you need supercharger boost vs static compression ratio calcs.
Since 95% of the time blower motors are not running on boost you need some compression. Again you need supercharger boost vs static compression ratio calcs.
Thread Starter
Race Director
Joined: Aug 2006
Posts: 18,346
Likes: 1
From: D / FW
Found an article in CHP and if I go with .51 thickness over the .29 I will loose 4 tenths down to 9.4.1 which is not that much.
With the MSD rev limiter I can get by with the 9.8.1 w/8 lb's boost at 6200 so I guess changing thickness not the easy fix.
Would like to drop to at least 8.8.1 with 8.5.1 better.
Heads just too dang small .
I feel a new set of heads in the offing w/76 cc chambers.
More research needed.
With the MSD rev limiter I can get by with the 9.8.1 w/8 lb's boost at 6200 so I guess changing thickness not the easy fix.
Would like to drop to at least 8.8.1 with 8.5.1 better.
Heads just too dang small .
I feel a new set of heads in the offing w/76 cc chambers.
More research needed.
