01 02 ws6 with ls6 block
There is a casting number on the back of the block just below the driver side cylinder head.
LS6 block is #12561168
Its a very hard cast # to see though. Much easier to see if the tranny is out. No major advantages to having the LS6 block either.
2001 F-Body
1. A small percentage of 2001 and 2002 LS1s actually had LS6 blocks which had a different part number and a darker metal cast
2. Starting 2001, all LS1s came with an LS6 intake manifold without an EGR system
3. Advertised HP output was changed from 305 to 310 on base LS1s and from 320 to 325 on WS6s and SSs
4. 2001-02 cars have a smaller cam from the Vortec truck engines to increase low end torque
5. 2001-02 cars had 28 lb fuel injectors like the 98 cars (albeit different part numbers)
6. WS6 cars had a redesigned 5 spoke rim which was more wavy
7. WS6 cars got less suspension upgrades from a base Trans Am suspension than previous years
8. Manual transmission cars all came with the Z06 clutch
http://www.ls1.com/forums/showthread.php?t=27515
The horsepower difference between the motors is mainly due to this difference and that is why some completely stock F-Bodies can smash other completely stock F-Bodies
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O2Z28Z06, 2006 CTS-V was an LS2...not an LS6.
LS6 did get better pistons for a while. The difference was coating. Eventually they all got that. This was not a performance enhancement, it was because GM couldn't build one of these without them sounding like a can of marbles when cold. Coating the piston skirts and tightening the clearance fixed that. They eventually coated the tops as well. This was to keep heat in the combustion chamber for performance and emissions.
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O2Z28Z06, 2006 CTS-V was an LS2...not an LS6.
LS6 did get better pistons for a while. The difference was coating. Eventually they all got that. This was not a performance enhancement, it was because GM couldn't build one of these without them sounding like a can of marbles when cold. Coating the piston skirts and tightening the clearance fixed that. They eventually coated the tops as well. This was to keep heat in the combustion chamber for performance and emissions.
Sorry for the confusion, should have said the engine was purchased from Crate Engine Depo in 2006, it is a CTS-V replacement engine, the pistons are black on top. The paper work that come with it said it was assembled and line tested in early 2006. And thanks for the info, I do have one more question. I have read on this site and others that bolting on LS6 243 heads on an LS1 ends up being 10:1 compression ratio. The LS6 is listed as having 10.5:1 ratio, am I missing something here or just some bad info? I received paper work with the engine stating it was 10.5:1 and premium fuel was required.
243 heads have 64.43 cc......................................
also head gaskets were .056 or .060 depending on years
hence 10.1:1 ls1 or 10.5:1 ls6


