roland427

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.

2th farmer

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?

Gordonm

The LT1 did not have a sway bar. The ZR1 did. The tach should be 6500 rpm redline.

BUGGSY1970

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.

SharkAttack

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.

jethro

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.

FOLDNTOP

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.

MidShark

Lots of good info. I believe that the correct # on the '71 Holley carb should be 3989021. List #4801, 780 CFM.

Rich

FOLDNTOP

You may be right it is a 780 however Dobbins book lists 3989014.

Bill Baird

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.

FOLDNTOP

Dobbins book I looked in was copyright 1981 so better research exists. Thanks for the correction.

eddy20

Note the tach was the normal tach used by the SB and Redlined @ 5600, but this was only on the AC equpiied LT1s.

FOLDNTOP

1971 LT-1 has 6500 rpm readline

5002vettester

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?

7T1vette

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!

62corvette

That would be a good indicator if it is an original blue tag. Those are reproduced.
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.

AJC 69 BB

Guys this post is 11 yrs old just a heads up!!

gbvette62

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!

62corvette

I'm fully aware of that. However, the question about the blue sticker was raised earlier today. Is it okay to respond to that? Yes, he restarted an old thread and should have started another.

Z06LMB

Never mind