Hey guys, I am looking at a '69 Corvette with an Oct. '69 build date. The car has a Muncie M21 with a P9KxxB assembly stamp. The partial VIN matching the car is present. Would a July-dated Muncie have been put in an October car?

Thanks for the help.

 

really hard if not impossible to grind down the texture of the aluminum case to hide an old stamp and restamp.. they could have got a unstamped case and stamped the numbers on, but if they did they were idiots for not making the date closer..

3 months is acceptable but somewhat extraordinary.

that large of a date spread would in my opinion be just another excuse for an otherwise correct car.. although trannys are faked a lot less than blocks so I would have more faith in its originality.

check all other cast codes and date codes for the case/sidecover/extension housing. pics would help.

if you are looking for an absolute correct car then do more homework.

 

Morning Neil. I have a 69 with an October 24th build date so it was close to yours. It has the M-20 trans and it's dated Oct 13th. P9R13A so it was only 11 days from the build date. The only thing I can think of is maybe your trans was sent back for a repair before being vin stamped and installed or maybe testing. I doubt very much it's not original or forged. If you were going to re stamp something it would have been just as easy to make a closer date. I would think it's original but there is probably a story behind that trans.

 

Hear is a shot of my Dec. '69 build date L-71. Hope it is useful.

Ralph
http://s598.photobucket.com/user/rpo...ml?sort=3&o=11

 

Thanks for the help guys. Here is a pic of the transmission and corresponding engine pad. Everything look ok?

 

You're fine. My car was built October 24th, 1969 and the trans (see below) is dated P9H16A (June 16th, 1969).

Remember, there was a slowdown at the St Louis plant starting early April, 1969, then the UAW strike which started on April 10th that lasted 8 weeks, with another 2 weeks to get back up to speed. During the last few months of Corvette production, it's not unusual to see larger than "normal" gaps in assembly dates because of this.

Ed

 

So, why don't I have a P9 in front of my T16B? Just curious.

Ralph

 

Hi Neil,
I think your two pictures show something interesting.... the same ganged stamp was used for the engine pad and the transmission case.... look how different (deeper, more displaced metal), the transmission case stamping is because of the softer material the stamp was stamped into!
Regards,
Alan

 

Sorry Ralph. I can't help you on that one. I've never seen a date code without the Muncie designator and the year. I've emailed a few people that are experts on Muncie stampings and no one that's replied so far has seen it either. I'll keep asking though...

Ed

 

Alan, is this something to be concerned with? I am traveling to inspect the car tomorrow.

Thanks.

 

Apologize for hijack of OP's thread, but experts appear to be here and subjects are related. From photos posted, stampings appear random as to location of VIN and date stamp (some over/under, some side by side, no pattern to orientation). Also it appears "P9" stampted a different time than date code.

My tranny code is Dec. 16, differential code is Dec 17, and a body build date of Jan 3 (timing was pretty close considering holidays). So, was too much eggnog being consumed on the assembly line during the Christmas season of 1968? Was someone absent from their assigned job? Anyway, I am familiar with the car's history for the last 40 years, and I am certain the tranny is original to the car. Besides, who would forge a P9 on a 4 year old car?

I am sure there are other cars out there with the same issue, but finding them might be difficult.

Thanks, Ralph

 

Ralph, while I'm not that familiar with the Muncie plant procedures, I DO know they assembled 3 speeds and 4 speeds for passenger cars and trucks. Just how many assembly lines they had is unknown, but each line would have a gang stamp to stamp the date code into the transmission (similar to the engine stamp shown below for the Flint engine plant). So if there were 2 lines for passenger car Muncie 4 speeds, there would have been 2 gang stamps. The same goes for 3 speed passenger car transmissions, 3 speed truck transmissions and 4 speed truck transmissions. However many lines there were, that would be the number of gang stamps used. Also note that the gang was loaded each morning with the current date and used all day, so all the Muncie 4 speeds assembled on the same line as yours on December 16th, 1968 "should" have the same anomaly.

The date was stamped after the transmission was assembled. Muncie would have had a directive on where to stamp the date on the transmission like the St Louis plant had a directive on where to stamp the partial VIN (see the AIM, UPC M20, Sheet A1 for that location).

The gang stamp would hold a certain number of characters, so why your transmission is missing the "P9" is a mystery. If the dies were physically missing from the gang holder, the rest of the characters would have been loose and they wouldn't have been able to stamp the transmission. They would have had to use blank dies for the "P9" and that would have been VERY unusual. I really can't see them running out of the two numbers/letters they would use the most ("P" for Muncie passenger car and "9" for 1969)!

But, stranger things have been found, so I'm not sure I'd worry about it too much unless you're getting the car judged. And even then the numbers are usually too difficult to see, so I don't believe they're judged. Someone in the judging staff can answer that question better than I.

By the way, thanks go to John Hinckley for some of this information.

Ed

 

Ed, thanks for sharing your expertise. I guess the mystery will continue. I have no plans for judging the car and am not really concerned about that. All I know is some variations exist and the tranny is original.

Thanks again. Ralph