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I purchased a 1971 Corvette LT-1 two days ago with all matching numbers, and date codes. The anomoly in the numbers is an engine suffix of CGY. All the data on LT-1's with CGY suffix state that the car would be a ZR-1. However the car has standard brakes, suspension, radiator etc. Its an early car with a build date of A31 which is August 1970. How can I explain the CGY suffix rather than CGZ???? What does it all mean?
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Re: 1971 coupe with CGY engine
Steve, it's my inderstanding that ZR1s also came with M22 transmissions. See if you can get the Muncie stamp on the trans. It should start with something like "PO.....".
Also, verify that the VIN derivative is also stamped on the trans.
The "stamper" at St Louis that day may have just made a mistake. Do you have any paperwork on the car, e.g. tank sticker, etc?1969 Riverside Gold Coupe, L71, 14,000 miles. Top Flight, 2 Star Bowtie. -
Re: 1971 coupe with CGY engine
Chris
The trans # is P1K29B.
The proper VIN of the car is on the engine and the trans.Comment
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Re: 1971 coupe with CGY engine
Steve, the Muncie stamp translates to:
P: Mucie 4 speed
1: 1971 model year
K: July
29: 29th day
B: M-21, "C" would be M-22
So, it's looking more and more like the stamper goofed.1969 Riverside Gold Coupe, L71, 14,000 miles. Top Flight, 2 Star Bowtie.Comment
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Re: 1971 coupe with CGY engine
Steve------
There were only 2 basic differences between the "CGZ" and "CGY" LT-1 engines for 1971 as delivered from the Flint engine plant to St. Louis. These are as follows:
1) "CGZ" engines had a "5 quart" oil pan; "CGY" engines had a "6 quart" oil pan. The "6 quart" pan has a longer sump and cannot be used in conjunction power steering;
2) "CGZ" engines were equipped with a 14" flywheel and associated bellhousing of GM #3899621. "CGY" engines were equipped with a 12-3/4" flywheel and associated bellhousing of GM #3858403 (or, POSSIBLY, 3840383).
It's not totally out of the question that a "CGY" engine was originally installed in your car. If the car is without power steering, the engine could have been originally installed in the car as-is. If so, the above 2 identifying features should be present. Another possibility is that the "CGY" engine was reconfigured at the St. Louis assembly plant to "convert" it to "CGZ" specs. This would have involved only the change of the 2 items described above. It's unlikely that this would have been done, but it's not impossible. If St. Louis had some "CGY" engines and no orders for ZR-1 optioned cars, they might have decided to reconfigure them. Of course, it's also very possible that the block was just mis-stamped at Flint.
You might check out the engine for the 2 items I described above. It's very easy and quick to do. If the car has power steering, then you don't need to check the oil pan; it WILL BE the "5 quart". The bellhousing number is cast on the right side of the bellhousing and is easy to discern. Please post what you find.In Appreciation of John HinckleyComment
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Re: 1971 coupe with CGY engine
Yes the car has power steering. The block casting date is H/27/0
Block ID is V0918CGY
Heads are 3927186 B/11/0
Vin on engine and trans S101253Comment
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Re: 1971 coupe with CGY engine
Steve----
At this point, then, checking the bellhousing number would be the most important thing to do.In Appreciation of John HinckleyComment
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Re: 1971 coupe with CGY engine
Its 3899621Comment
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Re: 1971 coupe with CGY engine
Steve-----
In that case, the engine was either reconfigured at St. Louis or the block was mis-stamped to begin with. It's also not beyond the realm of possibility that this is a "created" LT-1. If so, its "creator" might not have realized that the "CGY" code was for ZR-1 LT-1s only and, thus, mistakenly used it for his "creation".
Understand, though, that I AM NOT saying that the car is a fake; it's just a possibility that you should look into. To do this, you would need DOCUMENTATION for the car and/or a thorough and careful examination of the car, its components and the block/transmission stampings.In Appreciation of John HinckleyComment
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Re: 1971 coupe with CGY engine
Thanks. If I had to hazard a guess, it would be that because the car is very early in the model year, they reconfigured this CGY LT-1 engine to get the car out of the factory and on its way to a dealer. Since the VIN is in all its right places on the car without traces of resurfacing, it seems to be as you say a mis-stamp or deliberate act by the factory due maybe to parts shortage.Comment
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Addendum
By the way, there's another "problem" here that I noticed. The block was cast on August 27, 1970 and assembled/machined on September 18. However, according to the car's apparent VIN serial number, it was built on the 1st or 2nd of September of 1970. There's no way that a block cast on August 27th and assembled/machined on September 18 could have originally been installed in a car built at St. Louis on September 1st or 2nd. I would say that it's absolutely impossible. If the car left the factory with this engine, then it must have been a replacement engine installed at the factory. This did occur at some times due to a failed engine discovered at St. Louis. Then, the car would have gone "off-line" to "heavy repair" and another engine might have been installed. That would also be more consistent with the use of a "reconfigured" "CGY" engine.
Another "inconsistency" here are the head casting dates. These were cast on February 11, 1970. It's very unlikely that heads with this date would have been used on an engine assembled in September, 1970. It's not absolutely impossible, but it would be highly unusual.
So, we've got a lot of "inconsistenices" and "highly unusual" things here that all seem to have happened to the same car. I'd say that you need to look a LOT closer at a LOT of things about this car if it was sold to you (and PRICED) as an original LT-1.In Appreciation of John HinckleyComment
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Re: Addendum
The cars build date from the body tag is A31.
The plasticized blue tag with the matching VIN # to engine/trans/body inside the drivers door is noted as 9-70.Comment
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Re: Addendum
Steve------
That's all as it should be for a car of VIN serial #1253. The trim tag build date code of "A31" means 31st day of 1st month of production. For 1971 models, this means August, 31 1971. That's the day that the trim tag was installed on the completed body. The car was the built (and serialized) on September 1 (or, possibly, September 2). The blue certification door label, on which is imprinted the month and year of manufacture, should thus say 9-70, which it does.
All of this just refers to the manufacture of the car, itself. It says NOTHING about which engine was originally installed in the car. There are NO inconsistencies regarding the car's build; all the pieces "fit" and the information which you just provided regarding trim tag date code and certification label code fit perfectly with the VIN serial number that you provided earlier. I have no doubt, at all, that this is a 1971 Corvette which was originally built on September 1 (or 2nd), 1971.
The "inconsistencies" all revolve around the engine. Curiously, this is the primary component involved in the "creation" of an LT-1 from a base engine car.
A few other things that you might check:
(1) what is the tachometer redline (the point at which the red arc BEGINS)?
(2) does the car have a radiator supply tank installed on the right side fenderwell? If not, is there any indication that one was previously installed there (i.e. a bracket still there OR holes in the inner fender for a once-installed bracket)?
(3) Is the radiator shroud plastic or metal?
(4) Does the car have an original-type rear sway bar installed?
(5) Is the transmission crossmember (the center crossmember through which the exhaust pipes pass through holes) a welded-in type crossmember or are there 2 bolts on each side which attach it to the side frame rails?
These are all items which can be checked out quickly and easily. Post what you find and we'll go from there.In Appreciation of John HinckleyComment
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Re: Addendum
Joe
6,500 redline
No tank or holes
Plastic shroud
no rear swaybar
Welded crossmember
In addition the car has Transistorized ignition, with the sender in its proper place left side and harness from there to the distributor. Looks like it has always been there.Comment
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Tank Sheet On Tank...Or MIA? *NM*
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