71 Engine Code - LT1 or Not?
Thread Starter
Cruising
Joined: Oct 2008
Posts: 13
Likes: 0
From: Pittsburgh PA
71 Engine Code - LT1 or Not?
I bought this convertible in the fall of '08 thinking that it was a 350/270 w/ Auto, A/C, PS, PB, PW. Until this weekend when I started checking numbers:
Engine Block: Casting #3970010 2 H21 0 (which appears to be August 21 1970).
Vin Derivative Stamping: V0825 CGZ and C11S02367 (which matches the windshield post # and the vin # on my title). My restoration Guide says that CGZ is supposed to be a an LT1 with Holley, mechanical lifters and four-speed.
The intake maniforld is cast iron (not aluminum) with a date H 20 8 (obviously changed) and the car has a Rochester # 7041212DL 2380 (near correct date stamp).
The valve covers are finned aluminum and appear to be of the LT1 variety.
The water pump appears to have been changed (and is red in color, not chevy orange). The heads are also red in color but I havent pulled the covers to get their numbers.
The options on the car which appear to have come from the factory don't match-up with an LT1. What I can't figure-out is how that engine block - with those codes - got into the car in the first place. Remember, the vin numbers appear to match.
Is there a 1971 registry that I can check and will that help me try to figure out what I have?
Engine Block: Casting #3970010 2 H21 0 (which appears to be August 21 1970).
Vin Derivative Stamping: V0825 CGZ and C11S02367 (which matches the windshield post # and the vin # on my title). My restoration Guide says that CGZ is supposed to be a an LT1 with Holley, mechanical lifters and four-speed.
The intake maniforld is cast iron (not aluminum) with a date H 20 8 (obviously changed) and the car has a Rochester # 7041212DL 2380 (near correct date stamp).
The valve covers are finned aluminum and appear to be of the LT1 variety.
The water pump appears to have been changed (and is red in color, not chevy orange). The heads are also red in color but I havent pulled the covers to get their numbers.
The options on the car which appear to have come from the factory don't match-up with an LT1. What I can't figure-out is how that engine block - with those codes - got into the car in the first place. Remember, the vin numbers appear to match.
Is there a 1971 registry that I can check and will that help me try to figure out what I have?
Le Mans Master
Joined: Jan 2007
Posts: 5,485
Likes: 7
From: Peekskill NY
First off no LT-1 came with an auto trans & 72 only year LT-1 w/AC.
Tach should have 6,500 Redline (If I remember correctly).
There's been a ton of threads discussing LT-1 specifics. Do a search.
Glenn
Tach should have 6,500 Redline (If I remember correctly).
There's been a ton of threads discussing LT-1 specifics. Do a search.
Glenn
Drifting
Joined: Jun 2003
Posts: 1,455
Likes: 5
From: Upstate South Carolina
An LT-1 won't have factory AC and Auto, but maybe the AC and auto were added. Look in the engine at the passenger side frame. If there are two fuel lines, one feed and one return, then the car isn't an LT-1.
Safety Car
Joined: Sep 1999
Posts: 4,930
Likes: 11
From: AnyTown NJ
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Could be a bad/incorrect stamp or re-stamp...post a pic of the engine pad. The drivetrain/options you've described for a 71 should carry a CJK code on the pad.
Thread Starter
Cruising
Joined: Oct 2008
Posts: 13
Likes: 0
From: Pittsburgh PA
Now we're getting somewhere. I'll get a pic of the engine pad tonight and post it. This car does not appear to have the options of an LT1.
My thought at this point is that there was a mistake made when putting that engine into that car. And, due to the Vin number matching, it must have been done at the factory. I can't imagine that someone "faked" the stamps on or before '77, I don't see any sense in that.
What is the story of the labor strike that occured around that time? This car was assembled Dec 7, 1970. One of my buds is suggesting that with a shortage of proper parts, maybe the wrong engine block got installed in the car.
My thought at this point is that there was a mistake made when putting that engine into that car. And, due to the Vin number matching, it must have been done at the factory. I can't imagine that someone "faked" the stamps on or before '77, I don't see any sense in that.
What is the story of the labor strike that occured around that time? This car was assembled Dec 7, 1970. One of my buds is suggesting that with a shortage of proper parts, maybe the wrong engine block got installed in the car.
Drifting
Joined: Feb 2005
Posts: 1,438
Likes: 2
From: Melrose Florida
Highly unlikely as a factory "mistake", and impossible to verify without documentation - which begs the question, do you have the Protecto-O-Plate? It would answer the question right now.
Steve
Steve
Now we're getting somewhere. I'll get a pic of the engine pad tonight and post it. This car does not appear to have the options of an LT1.
My thought at this point is that there was a mistake made when putting that engine into that car. And, due to the Vin number matching, it must have been done at the factory. I can't imagine that someone "faked" the stamps on or before '77, I don't see any sense in that.
What is the story of the labor strike that occured around that time? This car was assembled Dec 7, 1970. One of my buds is suggesting that with a shortage of proper parts, maybe the wrong engine block got installed in the car.
My thought at this point is that there was a mistake made when putting that engine into that car. And, due to the Vin number matching, it must have been done at the factory. I can't imagine that someone "faked" the stamps on or before '77, I don't see any sense in that.
What is the story of the labor strike that occured around that time? This car was assembled Dec 7, 1970. One of my buds is suggesting that with a shortage of proper parts, maybe the wrong engine block got installed in the car.
Thread Starter
Cruising
Joined: Oct 2008
Posts: 13
Likes: 0
From: Pittsburgh PA
Steve,
No Protect-O, no build sheet, no previous owner info. Just the numbers on the block. I'll try to get that pic posted asap. Thanks
Frank
Here's the photo of the engine code:
No Protect-O, no build sheet, no previous owner info. Just the numbers on the block. I'll try to get that pic posted asap. Thanks
Frank
Here's the photo of the engine code:
Last edited by fcservak; Jan 19, 2009 at 07:59 PM. Reason: Added Photo
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 330
From: Indy Indiana
according to the corvette black book, car 2367 would have been built in october or november as car 2675 was the last one built in november.. maybe I am wrong but something does seem a tad fishy..
what is the date on your trim tag?
what is the date on your trim tag?
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Melting Slicks
Joined: Mar 2008
Posts: 2,336
Likes: 1
From: North Bellmore Ny
St. Jude Donor '09
The Z in the stamp looks deep to me. Is there a 71 code that starts with CG? if so I feel it may be a restamp. If not clean off the pad alittle better to see if you can find broach marks.
Thread Starter
Cruising
Joined: Oct 2008
Posts: 13
Likes: 0
From: Pittsburgh PA
The Trim Tag date is E07 which indicates Dec. 7, 1970 according to my references.
How is it suggested to "clean" the pad? I used some emory paper the first time around and that appears to be too abrasive. Steel wool or a scowering pad maybe? What are these broach marks that I'm supposed to be looking for?
Other 71 engine codes with "CG_" include: CGT (earlier base-engine code) which the car appears to be and CGY (ZR1 package) which it is not.
Frank
How is it suggested to "clean" the pad? I used some emory paper the first time around and that appears to be too abrasive. Steel wool or a scowering pad maybe? What are these broach marks that I'm supposed to be looking for?
Other 71 engine codes with "CG_" include: CGT (earlier base-engine code) which the car appears to be and CGY (ZR1 package) which it is not.
Frank
Last edited by fcservak; Jan 20, 2009 at 09:35 AM. Reason: Additional info.
Pro
Joined: Mar 2003
Posts: 742
Likes: 5
From: McMurray PA
For what it's worth, that pad doesn't look decked to me, especially with the grain on the right side.
Based on that fact, I would not use emery paper or anything abrasive to clean it which would cause lines, swirls, etc. in that surface. I'd just wipe it down with lacquer thinner at best to remove any grunge.
Based on that fact, I would not use emery paper or anything abrasive to clean it which would cause lines, swirls, etc. in that surface. I'd just wipe it down with lacquer thinner at best to remove any grunge.
