This is a question for you corvette Guru's: I am trying to track down the correct alternator for my 1980 base coupe-L-48. In the NCRS manual there are 5 listed date codes/casting numbers. Mine I would consider an early production with VIN ending in 7522, and build date of 11/79. I know its one of these 5 but which one? Would this be on the build sheet? Its there and appears to be in excellent condition but a NCRS restorer told me not to remove it. I know you guys are sharp so help the new guy out. Thanks.

 

Maybe something in here?

http://www.gmheritagecenter.com/docs...t-Corvette.pdf

 

First, a little rant- the farquing stupid terms 'early or late' as applied to a component have little to do with the car's VIN. After I die and go to h*ll, I will track down the guy that invented these terms and make his afterlife even more miserable. He'll be in line after I deal with the guy that invented neckties and the other w*nker that invented the term 'numbers matching'.

Now I feel better.

This is a classic case where the terminology trips up answering what should be a simple question. There were actually THREE different alternator rating during the production year- 61, 62 and 70 amps, depending on which options the car has. There was one part number rated at 61 amps, two at 63 amps and two others with 70 amps.

It appears that the 61 amp unit was discontinued at some point during the year and replaced by first one 63 amp unit, then at another point in time by a different 63 amp unit. So much for early and late.

The 70 amp cars had two different part numbers with the second number being introduced at some time during the year.

This means there's five different possibilities as you mentioned. First step is to determine which family you require.

If the car has RPO C49 (rear window defroster) or UA1 (heavy duty battery) then you need one of the 70 amp units. If no to both, you need a 61 or 63 amp unit.

As to when GM switched from one part number to another- it could have been at the very beginning of production, at the end or somewhere in the middle. If the NCRS guide doesn't give a time frame, then look at the assembly date on the alternator. If it's between two weeks to two months-ish earlier than the car assembly date, it's probably an acceptable part number.

 

Thanks, that gets me in the right direction and I do agree with your view on BS.... ABOUT early or late production. I did not realize that there would be a date on the alternator or are you referring to the date code? What is your opinion about removing the Build sheet.

 

Hi Mike,
While you're dancing with the devil will you also remember to take care of 'all original' ?!?!!
Regards,
Alan

Maybe you can arrange to have people's tongues catch on fire when they say it!

 

Thanks, I'll take a look.

 

[QUOTE=Chuck-C-80;1587002381]Thanks, that gets me in the right direction and I do agree with your view on BS.... ABOUT early or late production. I did not realize that there would be a date on the alternator or are you referring to the date code? What is your opinion about removing the Build sheet.[/QUOT


I'm sure this is a stupid question but how do you determine Heavy duty battery or not?

 

Chuck: Try this: http://www.corvetteactioncenter.com/...x.php?cmd=area

If the Allied-Vaughn folks have your VIN in their files, you can obtain a copy of the original dealer invoice for your 80. The invoice will list all the options installed on your car at St. Louis.

 

Thanks Mike.

 

There's a stamped date code on the alternator housing. It's always nice to see the tank sticker, but I can think of no reason to remove it.

I'll add 'all original' to the list as well as 'no hit body' 'original miles' and of course 'survivor'.

Having their tongues catch on fire is a good start, but would only happen after they've uttered the words. I'd prefer they self combust for even thinking them.

 

Thanks again Mike. Based on what you have brought to light it appears that the date code should be 1103122 for the 63 amp. I do not have any books to check if this date code reflects an alternator being built in Nov. 79 or the months before,if you have that info that would drive the nail home as my dad would say.

 

That's the part number, which corresponds to the second design alternator 63 amp unit for cars without C49 or UA1.

The date code would be a separate stamping of a single digit for the year, a letter for the month then two digits for the day of the month. A unit built on Nov. 15th 1979 would read 9L15 for example.

 

Excellent that's the final piece of info I needed. Now I can start looking for that needle in a hay stack. Thanks for all your help. This vette although not one of the most popular years has become a passion for me. It scored a first place in points at the show this past weekend and I think the wrong alternator cost me a few points, anyway again thanks for answering my questions.