Ive got the numbers matching 350 from my 72 Nova SS stuck in a corner in my shed. After reading this thread Im wondering why Im using up storage space hanging onto it. Ive never worried about numbers matching, survivor or original with either my Nova or Beaumont because neither of them qualified when I bought them. The fact that they are documented SS and SD cars is good enough for me.

@LT1caddy
Your partial quote was a little tough to follow - it initially looked like you simply quoted me and finished with the end.

Only upon further re-inspection did I notice you made replies inside the quote.

Date coding parts is in fact an extension of numbers matching.
Date coding parts is far from an exact science.
The date coding of components is generally practiced when a numbers car is found to have later service replacement parts - so date correct parts are searched for to make the vehicle more correct.

As an example, for a given vehicle/drivetrain there is a correct carburetor application number;
Id guess that more than 99% of the time the correct application number carburetor was used;
But there is inconsistent dating for engine components added at the vehicle manufacturing facility.
There are loose rules surrounding accepted norms for components, but since engines and components were placed newest up front, you can have a newer vehicle with an older dated engine, or older dated components.

We can agree to disagree on what the basic intent of numbers matching would be, thats fine;
I will be sticking to my opinion that the term as I have understood it was intended to imply that the vehicle vin matched the partial vin of the engine and transmission.
Unless the component came with a partial vin, it cannot be proven as original to the vehicle.

interesting.

Thanks for the additional information.

I always understood that Corvette judging was in a different class - but didn't realize that Corvette judging was such a departure from what I have become familiar with.

I have understood that the Corvette guys are essentially responsible for all the "number" lingo - and it getting adopted to many other vehicle types.

I wonder if date coding is more consistent with cars from Bowling Green - versus "more pedestrian" cars built in multiple plants across the continent(?).

My car will never be numbers matching (I have been unable to trace ownership before 1985- my car came with a NOM when I got it in 1995) - but I have an engine from another Firebird Formula from the same plant, and likely built on the same day as my car.
I have been trying to find everything that's as close to perfect as possible - which sent me down the date coded component search.

I am curious, incase you know, if there is a known date spread for 1969 Corvettes built with the Muncie three speed (unless I am mistaken I believe it was a 1969-only option) - I am finding date spreads (between casting, and car built date) in excess of a year.

-- Edited by unruhjonny on Tuesday 25th of April 2023 04:22:00 PM

As an aside, the 3-speeds in Corvettes were simply garden variety Saginaw 3-speeds with 2.54:1 1st gear. There is nothing special about it other than they probably got very dusty at the Corvette plant (since only 230 were made in 1969).

 

Here's a '68 3-speed that was at Legendary Motorcar back in 2004:

69 Vette question... NOT the only year for a 3 speed,(off the top of my head I'm not sure it was a Muncie) We had a guy in our club with a 66-67 Vette coupe, beautiful car, rare for all wrong reasons, it had a 3 speed tranny documented here in Canada.

The rarity of the 3 speed (who in their right mind would order it!!) would go AGAINST all I said about date coding. They probably built 3 months or more production between the orders. The 3 speed is RARE, so they would only have a few on hand dated close to the start of production.....An anomaly

Prior to 1969 there was only the saginaw, or older designed lower torque rated three speeds;
My understanding is that prior to 1970 all GM divisions which wanted a three speed behind a high torque engine, a Dearborn (read: Ford) three speed was used - but as far as I know, Chevrolet NEVER spec'd the Dearborn three speed, instead it required a transmission option (four speed or TH400).
In 1969 (afaik) all Chevrolet "SS" vehicles came standard with the Muncie three speed while for the non-SS cars, a big block (or more powerful engine) required ordering the Muncie three speed;
I believe that for the 1969 Camaro this transmission used RPO code MC1, while most other applications used M13.
(M13 was a typical "heavy duty three speed" RPO, while the more pedestrian three speed RPO was often M12.)

I believe that (oh lets say) a 1969 Chevelle SS-396, the Muncie three speed was a no-charge standard fare item, not an ordered item - and I have understood it was this also how it was with the 1969 Corvette.

For 1969 Chevrolet had exclusivity to this transmission (SM330) for the model year.
After 1969 all other divisions could use it, and it appears as though 1970 Chevrolet SS vehicles all dropped the three speed, and required their buyers select a four speed or TH400 option;
I believe there were some 1970 Chevrolet non-SS vehicles that if the 396 was ordered, you could opt for the Muncie three speed - but after 1969, Chevrolet almost exclusively used a (non car gear set) version of the Muncie three speed as a truck transmission.

Anyway, my query was because of the HUGE (read: massively abnormal) date spread that I have been coming across between casting or assembly dates of Muncie three speeds and a 1970 vehicle's build date.
The date spreads are normally a couple months, but in some instances they are nearly a year(!).

The Muncie three speed I found for my car (originally installed in a 1970 Tempest T-37 built in the Fremont plant) has a stamped assembly date of December 30 1969 (1970 model year);
The main case (where the assembly date is stamped) has a casting date of: I249 (Sept 24, 1969)
The tail housing has a casting date of: E89 (May 8 1969)
The side cover has a casting date of: L119 (Dec. 11 1969)
(I cannot make out any date on the front bearing retainer.)

IIRC the average accepted date window between build date and casting dates was two to six weeks.

The 1969 model year was, as far as I can tell, the largest production run for the 'SM330' Muncie three speed - and this was probably because Chevrolet used it in many of their cars that year.

-- Edited by unruhjonny on Thursday 27th of April 2023 01:42:32 PM

Just to maybe clear up another reason for anomalies... If I recall, 1969 there was an extended strike by UAW (not sure), production for the new model year was delayed...

This issue can be debated till the cows come home. To me a numbers car is block, tranny, rear end original to the car. If one goes to the extreme, then I would say there are very few " numbers matching " cars left on the sphere we call earth.

unruhjonny wrote

Prior to 1969 there was only the saginaw, or older designed lower torque rated three speeds;
My understanding is that prior to 1970 all GM divisions which wanted a three speed behind a high torque engine, a Dearborn (read: Ford) three speed was used - but as far as I know, Chevrolet NEVER spec'd the Dearborn three speed, instead it required a transmission option (four speed or TH400).

- Edited by unruhjonny on Thursday 27th of April 2023 01:42:32 PM

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 Chevrolet used a Borg Warner three speed in the Chevelles and maybe other Chevrolet models. A friend has a 1967 SS396 with its original Borg Warner transmission. Its a two owner car and I know both owners. 

Paul