This was posted on our OZ LS1 forum and I thought would be well received here. Special thanks to Strife - a forum moderator for the info.


Casting Number 241
Head: 1997+ LS1 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12559853 (1997-98)
12559853 (1999-00) (not sure why same PN)
12564241 (2001-03)
Combustion Chamber Volume: 66.67cc
Compression Ratio: 10.1:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches


Casting Number 243
Head: 2001 LS6 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12564243
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 706
Head: 1999+ LR4 4.8 Litre Truck
1999+ LM4 /LM7 5.3 Litre Truck
Material: Aluminimum
Part Number:
12559852
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 373
Head: 1999-2000 LQ4 6.0 Litre Truck
Material: Cast Iron
Part Number:
12561873
Combustion Chamber Volume: 71.06cc
Compression Ratio: 9.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 317
Head: 2001+ LQ4 6.0 Litre Truck
Material: Aluminimum
Part Number:
12572035
Combustion Chamber Volume: 71.06cc
Compression Ratio: 10:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Head: GMPP C5R
Material: Aluminimum
Part Number:
12480005
Combustion Chamber Volume: 38cc
Compression Ratio:
Intake Port Volume:
Exhaust Port Volume: 70cc

Head: GMPP C5R
Material: Aluminimum
Part Number:
12480025
Combustion Chamber Volume: 38cc
Compression Ratio:
Intake Port Volume:
Exhaust Port Volume: 70cc

Head: GMPP C5R
Material: Aluminimum
Part Number:
12480090
Combustion Chamber Volume: <30cc
Compression Ratio:
Intake Port Volume:
Exhaust Port Volume: 70cc

 

this is a good piece of info i hope you guys keep this post up

 

Its very incorrect...

First off...241's never came on 97 98 engines.

97 had a bastard casting number I can't remember as well as 806's which were carried over to 98. These bot had perimiter bolt valve covers.

99 went to 853's and some late ones got 241's. 00+ had 241's.

 

Also, "liter" is spelled wrong everytime it appears. I don't know what a "le tree" is, I'm guessing its french, which I don't speak.

Secondly...this information is in the sticky already as well as double, tripple....ect posted all over this site.

 

Old and incorrect info to say the least.

A good bit of info for third gen engines can be found at

www.chevythunder.com

you may want to check it out.

 

Actually, that IS the correct spelling. It's just Americans who routinely spell it liter.

 

"Secondly...this information is in the sticky already as well as double, tripple....ect posted all over this site."

"Tripple" must be another French word, then (trip-ley)....not to be confused by "ect", etc, etc, etc.

 

Hey well we are in America so I consider liter the American way to spell it and damn it Im an American. Take that as you will........

 

hahah your on the internet, you might me in America that doesn't mean everyone is. so show some consideration.

 

The OP is in Australia...it says so under "location"...that is the way the rest of the world spells liter...

 

I know its alot of data and i "think" ive started one but im waiting to see if its valid, i was wondering is there are or can be conversion CR list between different blocks and compatible STOCK heads, such as 5.7L with 317 heads with gaskets sizes and other info and so on and so forth? heres an example of what i came up with but i need some verification so if you all will, heres what i attemped:

LS1 standard sizes (i think)
Enter Cylinder Bore Size-----3.90
Enter Piston Stroke Length-------3.6
Enter Head Gasket Bore Diameter-------3.90
Enter Compressed Head Gasket Thickness----0.053
Enter Combustion Chamber Volume In CCs -----66.9
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') ---0
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') ---- -0.002
with this calculations,
Static CR is 10.16:1

now if this is correct now entering the 317 heads unmilled data with thinner gasket and this is what i got:

LS1 with 317 head sizes (i think)
Enter Cylinder Bore Size-----3.90
Enter Piston Stroke Length-------3.6
Enter Head Gasket Bore Diameter-------4.05
Enter Compressed Head Gasket Thickness----0.040 (cometics in mind)
Enter Combustion Chamber Volume In CCs -----72
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') ---0
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') ---- -0.002
with this calculations,
Static CR is 9.8:1

anyone with more experience in this PLEASE verify and/or correct this data for me if it needs it. i used this calc for reference http://www.csgnetwork.com/compcalc.html