[Z06] Pre-purchase inspection questions?
Thread Starter
4th Gear
Joined: Oct 2025
Posts: 4
Likes: 0
Pre-purchase inspection questions?
Hi all, is there a general FAQ or checklist of common items to go over when looking at a C5?
This particular car has super low miles at just under 17000. It also had a supercharger, cams, and pushrods, and has a 670 hp dyno sheet.
I don't NEED a car like this, but it seems well-priced, and I have always wanted a C5 Z06 I am coming from 3 past VW R32's, which were released around the same time, 2004. My first R32 I turboed and ran 12.2 1/4 mile and took 2 years first place SCCA Autocross. I know the Z06 is a completely different car, so there isn’t much to compare, but I have been working on cars for well 0ver 20 years at this point, so I am not scared to get dirty. With that said, this car doesn’t need anything, but I know with a SC there will be additional maintenance.
I just wanted to ask for a littler advice on some major things to look at before dropping 35k on a fast toy that will get me into trouble. I am looking forward to taking it to Tail Of the Dragon next year if it all works out.
Thanks!!
This particular car has super low miles at just under 17000. It also had a supercharger, cams, and pushrods, and has a 670 hp dyno sheet.
I don't NEED a car like this, but it seems well-priced, and I have always wanted a C5 Z06 I am coming from 3 past VW R32's, which were released around the same time, 2004. My first R32 I turboed and ran 12.2 1/4 mile and took 2 years first place SCCA Autocross. I know the Z06 is a completely different car, so there isn’t much to compare, but I have been working on cars for well 0ver 20 years at this point, so I am not scared to get dirty. With that said, this car doesn’t need anything, but I know with a SC there will be additional maintenance.
I just wanted to ask for a littler advice on some major things to look at before dropping 35k on a fast toy that will get me into trouble. I am looking forward to taking it to Tail Of the Dragon next year if it all works out.
Thanks!!
Drifting
Joined: Sep 2022
Posts: 1,485
Likes: 1,164
Hi all, is there a general FAQ or checklist of common items to go over when looking at a C5?
This particular car has super low miles at just under 17000. It also had a supercharger, cams, and pushrods, and has a 670 hp dyno sheet.
I don't NEED a car like this, but it seems well-priced, and I have always wanted a C5 Z06 I am coming from 3 past VW R32's, which were released around the same time, 2004. My first R32 I turboed and ran 12.2 1/4 mile and took 2 years first place SCCA Autocross. I know the Z06 is a completely different car, so there isn’t much to compare, but I have been working on cars for well 0ver 20 years at this point, so I am not scared to get dirty. With that said, this car doesn’t need anything, but I know with a SC there will be additional maintenance.
I just wanted to ask for a littler advice on some major things to look at before dropping 35k on a fast toy that will get me into trouble. I am looking forward to taking it to Tail Of the Dragon next year if it all works out.
Thanks!!
This particular car has super low miles at just under 17000. It also had a supercharger, cams, and pushrods, and has a 670 hp dyno sheet.
I don't NEED a car like this, but it seems well-priced, and I have always wanted a C5 Z06 I am coming from 3 past VW R32's, which were released around the same time, 2004. My first R32 I turboed and ran 12.2 1/4 mile and took 2 years first place SCCA Autocross. I know the Z06 is a completely different car, so there isn’t much to compare, but I have been working on cars for well 0ver 20 years at this point, so I am not scared to get dirty. With that said, this car doesn’t need anything, but I know with a SC there will be additional maintenance.
I just wanted to ask for a littler advice on some major things to look at before dropping 35k on a fast toy that will get me into trouble. I am looking forward to taking it to Tail Of the Dragon next year if it all works out.
Thanks!!
#2, with a 670HP supercharged engine, what about the rest of the drivetrain? Upgraded to stand up to that much HP???
#3, all changes and upgrades documented???
Cars like this with low miles and cheap are always suspect.
Pro
Joined: Jan 2001
Posts: 655
Likes: 351
From: San Jose CA
My advice here would be to find a specialty shop in your area to check out the car. 670WHP is not trivial in these cars, that's translating to 800-900 HP at the crank. Basically the entire drivetrain has to be aftermarket to survive that. If that car is running a factory short-block, it's probably not long for this world. I would suspect at these power levels it's probably been swapped to a Gen 4 (maybe iron) block with forged internals, but who knows.
The Transmission is next on the list, the C5 T56 units are not bad, but aren't robust enough to survive a 670WHP car that can hook-up. Trans built for something like this is a $3000-$7000 by itself.
You really need someone who knows what their looking at specifically in an LS build to determine if everything is sound. Where is the car located? we may be able to recommend a shop.
I want a full documentation of how the car's been built - who did what, when, and with what parts. In a perfect world you could talk to the builders.
Fair warning, this car is going to end up in a nasty class at SCCA events.
The Transmission is next on the list, the C5 T56 units are not bad, but aren't robust enough to survive a 670WHP car that can hook-up. Trans built for something like this is a $3000-$7000 by itself.
You really need someone who knows what their looking at specifically in an LS build to determine if everything is sound. Where is the car located? we may be able to recommend a shop.
I want a full documentation of how the car's been built - who did what, when, and with what parts. In a perfect world you could talk to the builders.
Fair warning, this car is going to end up in a nasty class at SCCA events.
Thread Starter
4th Gear
Joined: Oct 2025
Posts: 4
Likes: 0
Suspicious deal #1 would be a low mile Z06 for under 17K ???
#2, with a 670HP supercharged engine, what about the rest of the drivetrain? Upgraded to stand up to that much HP???
#3, all changes and upgrades documented???
Cars like this with low miles and cheap are always suspect.
#2, with a 670HP supercharged engine, what about the rest of the drivetrain? Upgraded to stand up to that much HP???
#3, all changes and upgrades documented???
Cars like this with low miles and cheap are always suspect.
Thread Starter
4th Gear
Joined: Oct 2025
Posts: 4
Likes: 0
My advice here would be to find a specialty shop in your area to check out the car. 670WHP is not trivial in these cars, that's translating to 800-900 HP at the crank. Basically the entire drivetrain has to be aftermarket to survive that. If that car is running a factory short-block, it's probably not long for this world. I would suspect at these power levels it's probably been swapped to a Gen 4 (maybe iron) block with forged internals, but who knows.
The Transmission is next on the list, the C5 T56 units are not bad, but aren't robust enough to survive a 670WHP car that can hook-up. Trans built for something like this is a $3000-$7000 by itself.
You really need someone who knows what their looking at specifically in an LS build to determine if everything is sound. Where is the car located? we may be able to recommend a shop.
I want a full documentation of how the car's been built - who did what, when, and with what parts. In a perfect world you could talk to the builders.
Fair warning, this car is going to end up in a nasty class at SCCA events.
The Transmission is next on the list, the C5 T56 units are not bad, but aren't robust enough to survive a 670WHP car that can hook-up. Trans built for something like this is a $3000-$7000 by itself.
You really need someone who knows what their looking at specifically in an LS build to determine if everything is sound. Where is the car located? we may be able to recommend a shop.
I want a full documentation of how the car's been built - who did what, when, and with what parts. In a perfect world you could talk to the builders.
Fair warning, this car is going to end up in a nasty class at SCCA events.
Melting Slicks
Joined: Mar 2023
Posts: 2,962
Likes: 1,703
From: North Coast
I suspect this car is like many I see. They supercharge and drive to club meets but really never drive in anger. Hence low miles.
#1 rule many mods do not add value to the car. Much of that price is close to what a stock un mod Z06 is worth. A Le Mans Z06 with low miles can go just over $30K.
If you know your way around just look for receipts and what was all done specific. Just saying headers or Cam mean nothing without part numbers. Also who did the work.
Like others said was the driveline upgraded. More power can break parts down the line not made for the extra power if driven hard. Driven easy they hold up.
Much is just common sense and making sure on the details. Often cars driven hard will have under body damage too. Get under the car.
I have seen similar C5 with superchargers sell for $24K with 30K miles. One last year was for sale for a while as some times modified cars can be difficult to move. Documentation often makes the difference.
I get guys calling daily wanting to know if we know what the past owner bought and installed on the car they just bought. Not fun not knowing and having issues.
#1 rule many mods do not add value to the car. Much of that price is close to what a stock un mod Z06 is worth. A Le Mans Z06 with low miles can go just over $30K.
If you know your way around just look for receipts and what was all done specific. Just saying headers or Cam mean nothing without part numbers. Also who did the work.
Like others said was the driveline upgraded. More power can break parts down the line not made for the extra power if driven hard. Driven easy they hold up.
Much is just common sense and making sure on the details. Often cars driven hard will have under body damage too. Get under the car.
I have seen similar C5 with superchargers sell for $24K with 30K miles. One last year was for sale for a while as some times modified cars can be difficult to move. Documentation often makes the difference.
I get guys calling daily wanting to know if we know what the past owner bought and installed on the car they just bought. Not fun not knowing and having issues.
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Drifting
Joined: Sep 2017
Posts: 1,966
Likes: 696
From: Avon Lake OH
My advice here would be to find a specialty shop in your area to check out the car. 670WHP is not trivial in these cars, that's translating to 800-900 HP at the crank. Basically the entire drivetrain has to be aftermarket to survive that. If that car is running a factory short-block, it's probably not long for this world. I would suspect at these power levels it's probably been swapped to a Gen 4 (maybe iron) block with forged internals, but who knows.
The Transmission is next on the list, the C5 T56 units are not bad, but aren't robust enough to survive a 670WHP car that can hook-up. Trans built for something like this is a $3000-$7000 by itself.
You really need someone who knows what their looking at specifically in an LS build to determine if everything is sound. Where is the car located? we may be able to recommend a shop.
I want a full documentation of how the car's been built - who did what, when, and with what parts. In a perfect world you could talk to the builders.
Fair warning, this car is going to end up in a nasty class at SCCA events.
The Transmission is next on the list, the C5 T56 units are not bad, but aren't robust enough to survive a 670WHP car that can hook-up. Trans built for something like this is a $3000-$7000 by itself.
You really need someone who knows what their looking at specifically in an LS build to determine if everything is sound. Where is the car located? we may be able to recommend a shop.
I want a full documentation of how the car's been built - who did what, when, and with what parts. In a perfect world you could talk to the builders.
Fair warning, this car is going to end up in a nasty class at SCCA events.
100%. Just saying, stock short block - Holy Crap! Sounds like a ticking time bomb. No mention of what type or brand clutch. Then there are the torque tube couplers, a solid drive shaft would be advisable. Also doubt the stock differential will last period if you ever hook her up hard. Should have a built C6 Z06 unit on a C6 subframe at that power level along with custom HD CV axle shafts.
Melting Slicks
Joined: Mar 2023
Posts: 2,962
Likes: 1,703
From: North Coast
I just saw on a Lingenfelter that is well sorted and well known. 25K miles and still sitting at $20K. This is the kind of car they built when John was still alive.
https://www.hagerty.com/marketplace/...6-38edc0d6f574
This is the kind of car that they fix all the details as a package vs many home built cars. Just a layer of security and generally they still sell below $30K. I think the one you are looking at is over priced.
Just don't shop with emotions and take your time as there are some good deals all the time. C5 Corvettes are not rare. But a tuner car like Lingenfelter may hold some extra value in the future over stock C5 Vettes. At one time no one wanted Shelby's.
The engine in the one is not a worry as the bottom ends are very strong. It is driveline and rear axle mounts and torque tube. If driven in anger and stock it will break the couplers or mounts.
https://www.hagerty.com/marketplace/...6-38edc0d6f574
This is the kind of car that they fix all the details as a package vs many home built cars. Just a layer of security and generally they still sell below $30K. I think the one you are looking at is over priced.
Just don't shop with emotions and take your time as there are some good deals all the time. C5 Corvettes are not rare. But a tuner car like Lingenfelter may hold some extra value in the future over stock C5 Vettes. At one time no one wanted Shelby's.
The engine in the one is not a worry as the bottom ends are very strong. It is driveline and rear axle mounts and torque tube. If driven in anger and stock it will break the couplers or mounts.
Drifting
Joined: Sep 2017
Posts: 1,966
Likes: 696
From: Avon Lake OH
The key weak points in a stock factory LS short block are the cast hypereutectic pistons and tight ring package. Heaven can only help their longevity once the oil temps happen to reach about 300 F. You can do this is a dead stock LS6 on the track (without an oil cooler) and most likely you will knock a chunk off a ring land off #7 or #8 piston - let along with enough boost to make 670wHP. As always YMMV.
Melting Slicks
Joined: Mar 2023
Posts: 2,962
Likes: 1,703
From: North Coast
Stock power limits
Keep in mind many make more power on the weak parts as they never hit the peak power unless they are racing. Most street drive so they stay under the limits.
The rods and pistons both are the needed upgrades.
See Brian Tooley racing for LS builds.
- Reliable range: In stock form, but with upgraded supporting components like heads, cam, and exhaust, the LS1 can reliably produce 400–450 horsepower.
- Maximum for a stock bottom end: Some experienced builders and forums suggest 500–550 horsepower is a reliable limit for a stock bottom-end, while exceeding 600 horsepower becomes a "hit or miss" situation.
- Underlying strength: The stock bottom end is considered strong for its class, with some people running well over 600 and even 800 horsepower with good tuning and supporting fuel systems.
Keep in mind many make more power on the weak parts as they never hit the peak power unless they are racing. Most street drive so they stay under the limits.
The rods and pistons both are the needed upgrades.
See Brian Tooley racing for LS builds.
Drifting
Joined: Sep 2017
Posts: 1,966
Likes: 696
From: Avon Lake OH
IIRC, Thompson Motorsports stated that the 5.7L short block in my car which consists of the GM aluminum block and cast crank with aftermarket forged 4340 alloy rods, ARP fasteners and forged full floating Diamond 2816 alloy pistons was good for 800cHP, where as the same block and crank fitted with stock GM powder metal forged rods and cast hypereutectic pistons is only rated to 500cHP.