Hi , I am going to look at a 71 LT1 and would like to know how to tell if it is the real deal . I am more familiar with c2 cars and would appreciate any help.

Regards Bill

 

http://forums.corvetteforum.com/c3-g...-tomorrow.html

WB

 

Original factory documentation with the car. The owner should have it and you should ask for it.

Good luck.

 

They might but I have to wonder how many people hang on to factory or dealer documentation? Especially after 40 years? I'd think it would be a rarity unless people are having them reproduced. A build sheet off the tank seems reasonable to hope for.

If there's doubt, check the numbers on the block, have someone look at broach marks?

When asking if it's 'real' I assume the buyer is looking for a collectible.

 

Genuine LT-1 owners have the documentation.

 

Just some guidelines:

1st. No 1970 or 1971 LT-1 had A/C

2nd. Emmission sticker on fire wall behind master cylinder should have letters AX on upper left corner for a 71.

3rd. All LT-1's are 4 speeds. (M20 was std , M21/M22 were optional)

4th. Tach has 6,500 RPM red line on 1970 & 1971 and on 72's w/o AC

5th. All 71 LT-1's came with A.I.R. system. If removed should still have manifolds with holes for the tubes, Car may have headers and if so ask to see old manifolds.

6th. LT-1's had copper radiator W/O a overflow canisiter on the passanger side fenderwell. There should also be no holes whers one had been mounted.


7th. All 70 / 71 LT-1's had Tranisitor Ign. system. That may have been removed. But if it is removed look for the 3 holes on the front face of the driver side inner fender well where the Amplifer box was mounter.

Take a flashlight and look in front of the front wheel or open hood and look at it from the front side. 2 holes on bottom and 1 on top.


8th. Should have a Winters snowflake intake manifold with casting # 3959594


9th. LT-1's had a Holley carb. so there is only 1 fuel line , no return line like a quadra-jet carb. Look along frame rail on passanger side for the single line. Also the fuel tank is different. There should be no nipple on the passanger side, side wall for a return line.

If you lay on your back under the rear wheel you can reach your hand up and feel for an indention on the passanger side. If there is a nipple that is capped off , then beware.

Also the single fuel line on a LT-1 was not the same line that was used to feed fuel on the 2 line set up. So if someone removed the return line the look of the 3/8 line is still different. Not a big difference but if you can look at a car with a 2 line set up then you can see what you do not want to find.

10th. LT-1's had solid lifters , but if the car does not then that is not to big a red flag. Many people do not like them and may have replaced with HYD. lifters during a rebuild.


11th. The hardest to fake and most expensive would be the 4 bolt main block. No # on the outside of the block can verify this.

Only way to verify is to remove the pan or have a lighted optical viewer and remove the drain plug.


12th. LT-1's use 2.5" exhaust pipes like the big block cars. But the manifolds were still 2" set up. So the pipes flair from 2 to 2.5" about 6 inches from the manifold. The exhaust hangar at the trans is also different. Look on line at the Corvette Central site and you can see both 2" and 2.5" hangars.

13th. As I recall the highest rear end gear was 3:36 if trans was a M20

And id Trans was a M21 or M22 the 3:55 was highest gear

M20 3:36 Economy

3:55 Standard

3:70 Performance


M21 / M22

3:55 Economy

3:70 Standard

4:11 Performance

14th. The 71 /71 LT-1 Aluminum valve covers should have a rubber oil cap not a twist in. These covers are very hard to find. All the catalouges sell the twist in cap style.

15th. LT-1's have the same heavy duty half shaft retainers as big block cars. look at the rear end side yokes, there should be caps with bolts. Base cars used U bolts with nuts.

16th. The rocker arms have a letter O stamped in them.

17th. The balancer on the crankshaft is an 8" unit not a 6"

 

I don't know why this would be true of LT-1 owners but not others. If I bought an LT1 in the day, doubt I'd still have the factory paperwork unless I expected to sell it in the future as a rare collectible. Even less likely if it's been through several hands. I suppose for a modest fee I could get factory documentation from a vendor on ebay.

 

I think SoCalErv covered it pretty well. We don't want to give away all our secrets to the posers out there. If you're stuck on buying an LT-1 (which I highly recommend,great car!) The 72 will tell you, right in the serial number, what engine it came with. That is one of the main reasons I went with a 72, I just lucked out and got all the documentation too. There are a lot of fakes out there. Good luck with your search. Keep us updated.

 

I went yesterday armed with the information the forum members posted and bought the car . I will get it home later this week .
The main thing I will need to find is the smog pump and hoses as they are long gone .
Thanks for the help .

Bill

 

Congratulations, you know we're going to need some pictures.