Compression Ratio?
Thread Starter
Supreme Member

Joined: Jan 2001
Posts: 7,164
Likes: 1
From: Someone owes me 10,000 posts
Car: 99 Formula
Engine: LS1
Transmission: T56
Axle/Gears: 342
Compression Ratio?
Is there a way to raise your compression ratio without taking off the heads, I don't think there is but I was just wondering.
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"Putting any amount of money into a RICE BURNER is like wiping your a$$ with a turd. "
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite
------------------
"Putting any amount of money into a RICE BURNER is like wiping your a$$ with a turd. "
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite
Supreme Member
Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
With the motor upside down, remove the oil pan and remove all the main bearing caps
and connecting rod caps. Carefully lift the crank out of the block. Have the crank offset ground (machine shop).020" on the rod journals.
Reinstall the crank with .020" undersize rod bearings, being carefull not to nick the journals with the rod bolt ends. Button up the oil pan.
This would increase the crank stroke .020"
and raise the compression about .3:1 on a 350
without removing the heads.
[This message has been edited by F-BIRD'88 (edited November 13, 2001).]
and connecting rod caps. Carefully lift the crank out of the block. Have the crank offset ground (machine shop).020" on the rod journals.
Reinstall the crank with .020" undersize rod bearings, being carefull not to nick the journals with the rod bolt ends. Button up the oil pan.
This would increase the crank stroke .020"
and raise the compression about .3:1 on a 350
without removing the heads.
[This message has been edited by F-BIRD'88 (edited November 13, 2001).]
Thread Starter
Supreme Member

Joined: Jan 2001
Posts: 7,164
Likes: 1
From: Someone owes me 10,000 posts
Car: 99 Formula
Engine: LS1
Transmission: T56
Axle/Gears: 342
Wow, so should I just flip my car over too. Just kidding, I was wondering because I have a warranty on my motor and I'm sure pulling the heads would negate that warranty. Thanks for the info though.
------------------
"Putting any amount of money into a RICE BURNER is like wiping your a$$ with a turd. "
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite
------------------
"Putting any amount of money into a RICE BURNER is like wiping your a$$ with a turd. "
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite
Actually, if you flip it upside down you could just unbolt your motor mounts and then unbolt the crossmember, then you could get right to the oil pan!!
I think you should give it a go
Brendan
I think you should give it a go

Brendan
Member
Joined: Nov 2000
Posts: 323
Likes: 0
From: mayfield, OH
Car: 82 Trans am
Engine: Twin turbo 350
Transmission: T-56
F-BIRD'88s idea would actually increase the stroke by .040". It would add .020 to both the top and the bottom of the stroke, and therefore give you twice the compression increase. THis is almost becoming worth the hassle
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hmm, maybe if u somehow got alot of carbon to build up inside the combustion chamber really quickly.
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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake
http://www.geocities.com/david_angel_16
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake
http://www.geocities.com/david_angel_16
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