LS1 or LS6
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Joined: Feb 2022
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From: NY
LS1 or LS6
Hi All, I'm looking at a 2000 C5 FRC. Seller claims that there is a LS6 Z motor with 243 heads. What is the best way I can confirm this? The car is out of state so I can't just go and look myself.
Any help is appreciated! Thanks!
Any help is appreciated! Thanks!
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From: Philadelphia PA (Birthplace of the USA, UNESCO World Heritage City)
Is it a transplant motor from a Z06 car, or a crate motor?
If the former, he can send you a picture of a VIN stamping on the block, which you can then enter into any VIN search service to confirm its a Z06 motor. Don't actually need to pay for the VIN report, the services will tell you what model car the VIN belongs to before you pay for the report.
If the latter, other members here can point to obvious exterior visual differences on the LS6.
If the former, he can send you a picture of a VIN stamping on the block, which you can then enter into any VIN search service to confirm its a Z06 motor. Don't actually need to pay for the VIN report, the services will tell you what model car the VIN belongs to before you pay for the report.
If the latter, other members here can point to obvious exterior visual differences on the LS6.
Melting Slicks
Joined: Dec 2004
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From: Sleepy Hollow- NJ
Is it a transplant motor from a Z06 car, or a crate motor?
If the former, he can send you a picture of a VIN stamping on the block, which you can then enter into any VIN search service to confirm its a Z06 motor. Don't actually need to pay for the VIN report, the services will tell you what model car the VIN belongs to before you pay for the report.
If the latter, other members here can point to obvious exterior visual differences on the LS6.
If the former, he can send you a picture of a VIN stamping on the block, which you can then enter into any VIN search service to confirm its a Z06 motor. Don't actually need to pay for the VIN report, the services will tell you what model car the VIN belongs to before you pay for the report.
If the latter, other members here can point to obvious exterior visual differences on the LS6.
...and just the heads could have been swapped, but the heads will have a '243' casting on them which are visually accessible on the front corner of the heads.Some non Z06 C5s (and Trans Ams) in 2001 and 2002 got the LS6 block due to an LS1 shortage in production. The block itself is the only LS6 part. No LS6 internals.
The only real way to confirm it's an LS6 block is the casting number. No way to confirm it's an LS6 with LS6 internals without opening it up. Maybe a dyno sheet would be indicative but there are a lot of variables and possible mods that could have been made.
Once you test drive it you'll have a good idea if you are driving 350hp, 385hp, or 405hp. Receipts for the motor purchase will also help.
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From: NY
...and just the heads could have been swapped, but the heads will have a '243' casting on them which are visually accessible on the front corner of the heads.Some non Z06 C5s (and Trans Ams) in 2001 and 2002 got the LS6 block due to an LS1 shortage in production. The block itself is the only LS6 part. No LS6 internals.
The only real way to confirm it's an LS6 block is the casting number. No way to confirm it's an LS6 with LS6 internals without opening it up. Maybe a dyno sheet would be indicative but there are a lot of variables and possible mods that could have been made.
Once you test drive it you'll have a good idea if you are driving 350hp, 385hp, or 405hp. Receipts for the motor purchase will also help.
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From: South Hill Wa
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
As long as the engine is sound and they are not asking more money for it because it has this or that, I wouldn't let that stop you from purchasing if the car is sound.
Aside from the cam and heads the rest of the LS6 has no real special parts in it. It's not quite the holy grail that some Z owners make it out to be. Now stock for stock comparing an LS1 to an LS6 by all means it is a fantastic powerplant.
Also the exhaust is the same except the axle back portion is made out of Titanium on a Z.
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
As long as the engine is sound and they are not asking more money for it because it has this or that, I wouldn't let that stop you from purchasing if the car is sound.
Aside from the cam and heads the rest of the LS6 has no real special parts in it. It's not quite the holy grail that some Z owners make it out to be. Now stock for stock comparing an LS1 to an LS6 by all means it is a fantastic powerplant.
Also the exhaust is the same except the axle back portion is made out of Titanium on a Z.
Aside from the cam and heads the rest of the LS6 has no real special parts in it. It's not quite the holy grail that some Z owners make it out to be. Now stock for stock comparing an LS1 to an LS6 by all means it is a fantastic powerplant.
Also the exhaust is the same except the axle back portion is made out of Titanium on a Z.
another vote with the same perspective. If the car is sound and priced appropriately...as long as it runs & drives as it should, it could be a nice find. The LS6 has benefits over the LS1 and the LS6 is a better starting point stock vs. stock. But if you plan to mod both are extremely mod capable and both variants make for great foundations. It already has the better #243 heads and a titanium axle back. Which reduces the need to source these additional upgrades. Especially if the exhaust note of the titanium does it for you. If not just sell it and recupe some funds toward the axle back of your liking.
Neither the heads or the axle back demand a premium or significance in up charge.
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Some good advice above. Some other things I'd like to add. I also have a 2000. That said, if the car has had the Z06 heads and exhaust added, but the shortblock is still 2000 LS1, that's not all bad. The 2000 C5 LS1 had the best performing factory cam of any year built.. Only the LS6 cams from '01-'04 were better. If all else fails, you could verify the cam with a dial indicator. The 2000 cam was the only LS1 cam that has 1/2" lift. With the 243 heads, Ti axle back exhaust, some boltons, and a good tune, you'll have a mid to low 12 second ride there that still pulls 27mpg on the highway.......
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