1971 LT 1 How to prove that it is anoriginal LT1
#1
1971 LT 1 How to prove that it is anoriginal LT1
Just bought a 71 coupe. The console says it has 330hp and it has a factory rear sway bar. The motor is not original and the vin has an S in it. Is there any way to prove that it is an lt1 since there is no tank sheet? Thanks.
#2
Melting Slicks
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CI 6-8-9 Veteran
No gas line return
Transistorized ignition box attached to left fender
tach redline
VIN does not mean anything on a 70-71 there is a t in the 72 vin. IMHO without documentation little reliability as to the authentic LT1. But, without an original engine does it matter that much?
Transistorized ignition box attached to left fender
tach redline
VIN does not mean anything on a 70-71 there is a t in the 72 vin. IMHO without documentation little reliability as to the authentic LT1. But, without an original engine does it matter that much?
Last edited by 2th farmer; 03-08-2006 at 06:51 PM.
#4
Racer
What does it matter?
If it does not have the original engine it is whatever you make it. LT1, BIG BLOCK, small block, fuel injected, or 327. It will never be original so whatever it has under the hood is what it is.
If you want to know what it WAS you need original documentation-tank sticker, factory invoice, dealer invoice, protecto plate, or the original owner to ask.
If it does not have the original engine it is whatever you make it. LT1, BIG BLOCK, small block, fuel injected, or 327. It will never be original so whatever it has under the hood is what it is.
If you want to know what it WAS you need original documentation-tank sticker, factory invoice, dealer invoice, protecto plate, or the original owner to ask.
#5
Safety Car
Some of these are mentioned above and many can be changed by a previous owner, but here goes...
- Domed hood (same as on big block cars)
- Open air filter element with chrome lid
- GM high rise aluminum intake manifold
- Aluminum valve/rocker-arm covers
- Transistor ignition (believe it did not come on all LT-1 models)
- Must have a 4-speed tranny (auto not available w/ LT-1)
- Can not have factory A/C (unless year model 72, but only ~240 made)
- 6500 rpm tach redline
- Single metal line from fuel tank (base engines had two lines)
- Heavy duty u-joint clips for the half shaft connections to the differential yokes (in lieu of the ones that look like small muffler clamps)
The engine code was added to the VIN in 1972, so prior years can not have their engine determined/verified by the VIN. Hope this helps.
- Domed hood (same as on big block cars)
- Open air filter element with chrome lid
- GM high rise aluminum intake manifold
- Aluminum valve/rocker-arm covers
- Transistor ignition (believe it did not come on all LT-1 models)
- Must have a 4-speed tranny (auto not available w/ LT-1)
- Can not have factory A/C (unless year model 72, but only ~240 made)
- 6500 rpm tach redline
- Single metal line from fuel tank (base engines had two lines)
- Heavy duty u-joint clips for the half shaft connections to the differential yokes (in lieu of the ones that look like small muffler clamps)
The engine code was added to the VIN in 1972, so prior years can not have their engine determined/verified by the VIN. Hope this helps.
#6
Heel & Toe
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If it was originally sold in Canada then you should be able to get the information from GM of Canada. It was quite a while ago, but I got copies of the build information for my 71 LT-1.
#7
Drifting
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1971 Lt-1
One of my old sources is the Vette Vues Fact Book of the 1968-1972 Stingray by M.F. Dobbins.
I had a numbers matching 1971 Lt-1 convertible and here are a few clues in no particular order if you don't have the correct engine.
- Engine: CGZ suffix
- Valve covers finned aluminum with rubber oil filler 1971 only
- Intake manifold with numbered runners
- TI Ignition distributor tag for ti - 1112101
- TI box or holes for same. TI came with Lt-1 and LS6 only. ( TI and no holes for expansion tank good clue to Lt-1)
- Big block copper rad and support no holes in right inner fender for expansion tank. No expansion tank on Lt-1. Big blocks had the tank.
- 6500 rpm tack
- open element air cleaner
- big block hood with no holes for 454 emblems
- stripes were same thickness top and bottom 71 and 72
- 750 holly no. 3989014
- HD suspension shocks sway bar and rear spindle supports was standard equipment with the Lt-1
- no AC, not avaiable
- m20 or m21 only... m22 in ZR1
- 3970010 block casting. also used in 71 only with TH 400 cars had same internals as 330 LT1
- 202 heads with screw in studs
- solid lifters
- console ID
- emissions lable
For what its worth.
I had a numbers matching 1971 Lt-1 convertible and here are a few clues in no particular order if you don't have the correct engine.
- Engine: CGZ suffix
- Valve covers finned aluminum with rubber oil filler 1971 only
- Intake manifold with numbered runners
- TI Ignition distributor tag for ti - 1112101
- TI box or holes for same. TI came with Lt-1 and LS6 only. ( TI and no holes for expansion tank good clue to Lt-1)
- Big block copper rad and support no holes in right inner fender for expansion tank. No expansion tank on Lt-1. Big blocks had the tank.
- 6500 rpm tack
- open element air cleaner
- big block hood with no holes for 454 emblems
- stripes were same thickness top and bottom 71 and 72
- 750 holly no. 3989014
- HD suspension shocks sway bar and rear spindle supports was standard equipment with the Lt-1
- no AC, not avaiable
- m20 or m21 only... m22 in ZR1
- 3970010 block casting. also used in 71 only with TH 400 cars had same internals as 330 LT1
- 202 heads with screw in studs
- solid lifters
- console ID
- emissions lable
For what its worth.
Last edited by FOLDNTOP; 03-09-2006 at 11:19 PM.
#9
Drifting
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Originally Posted by MidShark
Lots of good info. I believe that the correct # on the '71 Holley carb should be 3989021. List #4801, 780 CFM.
Rich
Rich
#10
Pro
The Corvette Black Book (2005 version) lists the Holley R4801A #3989021 as the proper carburetor for the 1971 LT1. The NCRS 1968-1982 Corvette Specifications Guide agrees.
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#13
Drifting
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Originally Posted by eddy20
Note the tach was the normal tach used by the SB and Redlined @ 5600, but this was only on the AC equpiied LT1s.
#14
1971 Lt-1 I.D. Help
On my original door blue door tag on the bottom left corner it was originally type with several numbers and letters. What's readable is 105cgz. May have more numbers in front. Anyone out there have info on this?
#15
Team Owner
If the engine is original to the car and if it is a 'real' LT-1 engine, the engine code will be CGZ; if it is a ZR1 car, it will have a CGY engine code. All other codes are NOT relevant to the LT-1 option.
Keep in mind that ANYTHING can be faked/cloned. The engine block stamp can be re-stamped as well as all the correct LT-1 parts and assemblies could be changed. MANY owners change over the valve covers, swap to the LT-1 hood with proper striping, etc. so that their car resembles an LT-1 vehicle. SOME owners go 'all the way'.
There is NO way to be certain that any car came from the factory as an LT-1 optioned vehicle. But, there are subtle differences that most owners don't know to include in their 'remodel' efforts. Your best insurance would be to trace that car's history and talk with past owners to assure that it is real. Sellers who have re-stamped their engine blocks only do so to deceive potential buyers. So beware!
Keep in mind that ANYTHING can be faked/cloned. The engine block stamp can be re-stamped as well as all the correct LT-1 parts and assemblies could be changed. MANY owners change over the valve covers, swap to the LT-1 hood with proper striping, etc. so that their car resembles an LT-1 vehicle. SOME owners go 'all the way'.
There is NO way to be certain that any car came from the factory as an LT-1 optioned vehicle. But, there are subtle differences that most owners don't know to include in their 'remodel' efforts. Your best insurance would be to trace that car's history and talk with past owners to assure that it is real. Sellers who have re-stamped their engine blocks only do so to deceive potential buyers. So beware!
Last edited by 7T1vette; 05-06-2017 at 04:19 PM.
#16
Safety Car
The original blue tag info prior to the 1972 model year was stamped with running it over the protectoplate.
Can you see anything else on the tag? It should also have tranny code dating.
#18
Race Director
Yep, and the OP never even responded to this post again. I guess he didn't like the answers he got.
For that matter, I guess he didn't like the Forum much, since he hasn't checked in since Nov. 2006!
For that matter, I guess he didn't like the Forum much, since he hasn't checked in since Nov. 2006!
Last edited by gbvette62; 05-06-2017 at 09:10 PM.
#19
Safety Car