matching numbers location...?

[cesully]

Folks,
I have a 78 Silver Anni- on my aluminum intake there is a number towards the back- is this supposed to "match" the last digits on my VIN #?
It does not match- I'm wondering if i do not have the correct intake.

Also is there a engine block # that is supposed to match my VIN? I can see a number on my block near the water pump but is is not even close to my VIN#

Can anyone advise me here in a quick Numbers Matching 101 course?

Thanks for all you support...

Sully

 

[early shark]

There should be a machined flat pad on the passenger side front of your engine block. There should be 2 sets of different height stampings on this surface. 1 set will give the assembly date of the engine, the other should be a deriviative of your vin# located on the inner winshield post. If you find that there is no resemblence of any kind to the second set of stampings to your vin number, you most likely have a replacement motor sitting in your 'vette.

 

[Mac]

The number on your intake is likely a casting number. If you post it, someone will be able to check and tell you whether it's a Corvette part and of what vintage.

-Mac

 

[Vettehead Mikey]

Can anyone advise me here in a quick Numbers Matching 101 course?

The problem here is that there's no one definition of 'numbers matching', everybody has their own ideas of what it means.

 

[cesully]

thanks all for the input...

Sully

 

[early shark]

That statement is not exactly true.


The term "matchig numbers" was meant to convey that a portion of vin derivative on the car was also stamped onto certain components of the car, and that is was inferred that these components were correct AND original to this particular vehicle.

In the later year Corvettes, there are only 3 components that have a portion of the vin number that most refer to as 'matching numbers". The engine block, the manual transmission case, and the chassis frame.

Every other component will have either a raised embossed casting number or a recessed stamped number that could or would contain the proper number used for that application on the Corvette model and or for the proper time period prior to the body build date code, this is often what unknowledgable persons refer to as "matching numbers", which is used in the wrong context of what "matching numbers" was originally conceived to be used for.

 

[JohnZ]

The same VIN derivative that's stamped on the block pad is also stamped on automatic transmission cases as well - both manual and automatics have them.

 

[cesully]

oh no...!

So... my engine, 1978, should have a number stamped on it similar to my VIN tag that is on the drivers side a-post. I'm concerned because I checked this number on the block, and although i could read most of the numbers ( i have to get in there and wipe it clean) that is on the passengers side near the water pump and it does not seem to jive with the VIN tag.


?????

 

[JohnZ]

You should have two stampings on that pad - one that was stamped at the engine plant with a larger font in the format "Vxxxxyyy" where the x's are the month and day and the y's are a three-digit alpha code starting with "C" (CHW, CLM, CLR, CLS, CMR, CMS, or CUT). The other one, in slightly smaller font, stamped at the car assembly plant, will be in the format "18Sxxxxxx", where the x's are the last six digits of the car's VIN number on the plate on the inside of the driver's side windshield post. If the stampings on your pad don't match these formats, it's not the original engine.

 

[cesully]

Thanks John,

I seem to remember that it was a narrow pad with only 1, 8-9 digit number on it. I checked from above with a flashlight....I only have a small vantage point but thought I could see the whole pad by moving my head...the digits I did see didn't seem to co-inside with my VIN#.

Sully

You should have two stampings on that pad - one that was stamped at the engine plant with a larger font in the format "Vxxxxyyy" where the x's are the month and day and the y's are a three-digit alpha code starting with "C" (CHW, CLM, CLR, CLS, CMR, CMS, or CUT). The other one, in slightly smaller font, stamped at the car assembly plant, will be in the format "18Sxxxxxx", where the x's are the last six digits of the car's VIN number on the plate on the inside of the driver's side windshield post. If the stampings on your pad don't match these formats, it's not the original engine.

 

[Vettehead Mikey]

That statement is not exactly true.


The term "matchig numbers" was meant to convey that a portion of vin derivative on the car was also stamped onto certain components of the car, and that is was inferred that these components were correct AND original to this particular vehicle.

In the later year Corvettes, there are only 3 components that have a portion of the vin number that most refer to as 'matching numbers". The engine block, the manual transmission case, and the chassis frame.

Every other component will have either a raised embossed casting number or a recessed stamped number that could or would contain the proper number used for that application on the Corvette model and or for the proper time period prior to the body build date code, this is often what unknowledgable persons refer to as "matching numbers", which is used in the wrong context of what "matching numbers" was originally conceived to be used for.

OK, so I'll add YOUR definition to the other dozen or so that I've seen, each one coming from someone who's convinced that they're right and all the others are wrong. :L

 

[tomtom72]

Hi Sully, I would suggest buying a copy of the NCRS "Corvette Technical Information Manual & Judging Guide" for your year corvette. In there will be the Vin # spread, Engine Codes, Tranny Codes and a whole lot of stuff to help you determine how original your car is, or to what degree it is a numbers' matching example of a 78 S/A. I would have given #'s in this post, but I only have the guide 1970 thru 1972. I will give the three letter engine suffix listed in NCRS pocket guide: L82 / 220hp / 4 spd = CMR. The tranny codes are: Warner 4 spd, Aluminum case, wide-ratio(2.85:1 1st gear) = S6 ; Warner 4spd, Alum case, wide-ratio(2.64:1 ist gear) = ZU ; Warner 4 spd, Alum case,close ratio(2.43:1 1st gear) =ZW. The block casting #'s are 3970010 = all 350 cu 175, 185, 220 hp; 376450 & 460703 are 350 cu of uncertain usage application. The alum. intake manifold casting # is = 458520; the head #'s are 462624 = all 350 cu engines. The exhaust manifold casting #'s are: 3932461 = left , 3932461 = right, no that's not a typo l & r manifolds are same casting #'s. Carb # for M/T = 17058211, rochester mod M4MC = 220 hp 350 w/4spd. The distributor # is 1103291, Alternator # 1102484 or 1102908. These #'s came from the C3 pocket guide. tt72

 

[DDLS3]

Scott has pictures of the vin locations posted on his website www.c3sharktank.com The term matching numbers, is intended to indicate that the car is original with the factory installed engine, tranny, and differential (major components).

 

[cesully]

Good News!

After a good soaking from a can of brake cleaner I uncovered some more numbers below what I originally was able to read (and through you guys help) and I was able to discover 6 digits on the block pad that "match" my VIN# by the windshield.

Boy am I relieved.

thanks tomtom for the additional info...

I'm at peace now... until the next minor cricis... good job guys...

Sully