Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stamping.

[Bob P.]

I need your help to clarify the following information on this '71 Corvette. The car has a CE block in it and the engine pad is stamped accordingly. I would like to determine what the stamping means. I have also attached the block casting date, which I need help in reading. The first number or letter isn't very clear to me. Final, I have a picture attached of the transmission case stamping. The vin is correct for the car on it, but the other stamping that identifies the type of transmission doesn't make sense. It appears that it is for a '70 model year, car was produced in December of '70 so a '71 model year. It also appears that the letter at the end of the stamping was crossed out and then a "A" was added. Can't tell what the letter that was crossed out was, but wanted to see if those of you with more experience looking at these types of things have ever seen this before. Final, I would like your input on what the draw backs are to purchasing a car with a CE block. Thanks for your help and I hope all of this makes sense! The pictures are located on this link.http://s615.photobucket.com/user/Bob.../71%20Corvette

[Patrick B.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Both the CE stamping and the casting date indicate a replacement fitted block or short block cast and manufactured in 1974. The X out on the transmission looks like it had been stamped "B" incorrectly and was changed to "A" for wide ratio. Oddly, the Muncie stamp is for the 1970 model year. You described the VIN is as a 71, but the photo does not show enough of it to determine that. A 1974 CE block suggests that the block was replaced by a dealer during the warrantee period. If so, the heads, manifolds and other parts of the engine are probably original. This is better than a Buba replacement of the whole engine with miscellaneous parts at some later date, but you are still missing the original block.

[Bob P.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Thanks for your help Patrick. You confirmed what I thought as well about the casting date. I was trying to make out what the first letter or number was but couldn't determine it, maybe you can. The VIN on the car is 194671S103915. It is a '71 LT1 convertible. Car was produced on December 14, 1970. Not sure why the transmission stamping is for a '70. The car checks out to be a real LT1, tach is correct, I also looked at the rear end to see if heavy duty caps were present and they are. It's missing some things other than the original block, AIR primarily, but it looks to be a solid car. What do you see as the down side and limitations of purchasing a car like this in terms of NCRS requirements?

[Patrick B.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Robert--- I'm not particularly knowledgeable on the judging aspects of NCRS, but I think you would lose a lot of points for a block with an incorrect year and a transmission that is probably original but stamped strangely. Make sure this car has TI before you conclude it is an LT-1. Also, a wide ratio transmission would be unusual for an LT-1. Most had a 3.70 rear and a close ratio. Check the rear end codes. If it happens to be a 3.55 or 3.36, a wide ratio would be more believeable.

[Bob P.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Patrick, The TI module is still mounted to the driver side front fender well. The distributor has points in it now, but the owner has the part that replaces the points and condenser as well as the correct coil. Tried to get pictures of the rear end where the stampings where, but they didn't turn out to good. I can try and post them.

[Bob P.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Here are the pictures. Can't make out the first letter of the code, but it looks like _ A W 250 2. Since all the codes for '71 start with A, I'm assuming it is a AA meaning a 3.55 ratio, W for Warren and 250 being the julian date and 2 being the shift. The 250th day of the year would be Sept. 7, 1970 which would make sense. Take a look at the link and you can see. http://s615.photobucket.com/user/Bob.../71%20Corvetterear differential.jpgrear differential 2.jpg

[Patrick B.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Having the TI module and harness on the car is good evidence of the LT-1 engine. Check that it has the right heads with push rod guide plates. I have a 70 LT-1 and I am not familiar with the 71 rear axle codes. The 70 codes identified which rears had cap-type yokes, and the 71 codes do not. I see AA is the 3.55 code, but AW is the code for 3.08.

[Bob P.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

The TIM&JG states that all big blocks and LT1's have heavy duty block caps. I think it might be wise to try and take a couple additional pictures of the rear differential. These didn't come out to well. The transmission case is being stamped for 1970 model year is a bit puzzling, especially when it has a clear VIN stamp that matches the car. I was able to check one of the heads by removing the oil fill plug and looking at the casting number. Not sure what the guide plates are or look like??

[Patrick B.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

Instead of having pressed-in rocker arm studs and push rods guided only by the holes on the heads, LT-1s had screw-in rocker studs that bolted down a flat plate for each cylinder with two slots to guide the push rods. Remove the rocker covers to see if the heads have original dates and guide plates. If the heads are correct and have the right casting dates for the car, it will help confirm that it is a real LT-1 car with a warrantee short block.

[Michael W.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

What do you see as the down side and limitations of purchasing a car like this in terms of NCRS requirements?

Assuming the casting number is correct, the casting date would get a 175 point deduct. The pad would not be judged at all so having a CE engine would not help or hurt.

Most transmission numbers are not often readable with the car sitting on the ground and are not judged.

[John H.]

Re: Need Help Clarifying Engine Pad Stamp, Block Casting Date and Transmission Stampi

What do you see as the down side and limitations of purchasing a car like this in terms of NCRS requirements?

From a judging perspective, the major points loss would be in the engine. If the block casting number isn't 3970010, that's a 350-point deduction; if it's 3970010 and the casting date doesn't make sense with the car, that's a 175-point deduction. In either of these two cases, block judging ceases at that point (no judging or scoring of the front pad).