car was built on my birthday

Yeah, but your waaaaaaay older than that :D

Dan

Youre not far behind

I agree James, but my Gold Z has a 4.10 rear and it is just not reasonable to drive except around town. On the interstate it is a joke and at 60 miles per hour it is screaming and I am getting dusted by all the other traffic. So will be interesting to drive the car with a 3.31. A 3.73 is not as bad.

I believe now that the car has 3.31 gears per the stamp on the axle tube. So what is weird to me is the the build sheet has KK, and the rear end is CF with a axle tube stamp of 0412 that is right in line with all the other stamps of the 052 build on the Trim Tag. If the axle tube stamp was not in line with the build of the car it would obvious it was flipped out. Perhaps the original owner early had the rear end changed?
Thoughts?

Not an answer to your axle question, but on my 69 that I bought new, and still have, I ordered the K85 63 amp alternator. It's on the build sheet too, but the car came through with a 37 amp alternator. I didn't discover that until a few years later. I suppose there are other stories about mismatched parts vs build sheets.

Viz

Anything was possible,but unless you have a signed affidavit or any other docs stating this car was built with a 3.31,it will be believed that it is not the original born with rearend housing,based on the accompanying buildsheet showing 4.10.
People have been looking for correctly dated replacement components for their cars since these cars rolled out off the assembly line,and still are today for this very reason.

What trans does the build sheet say it came with M20 M21 or M22 that would be a clue of what gear originally came in the car

I don't think that will help John,as all three 4 spd. transmissions behind this Chevelle could've received a 3.31,3.55,3.73 or 4.10 gear back then from the factory.
I suspect someone swapped in the rear axle tube afterwards,who didn't have access to that partial buildsheet,or if they did,they weren't savvy to noticing the G80 & G84 notation of 4.

[QUOTE=Mr70;1366286]

I agree, I think someone swapped out the rear end, but many years ago. The car per the seller has not moved in 30 years. The last inspection sticker on the front window is 1987. The amount of gunk that I had to scrape off the axle tube had been there a long time. I am guessing that someone got the car with the 4.10's and said...oh hell no I can't drive this thing with this gear and put a new rear end in the car. I say this because the date of the rear end is consistent with all the other date codes of the other parts on the car. Or under the more unlikely scenario the car was born with a 3.31. I am guessing, seeing that the car still has the original engine the 3.31 may have been in the car for a long time. Not saying that an original engine can't remain with a 4.10 but perhaps the 3.31 helped along the way??
So I drove the car for the first time yesterday. It runs like a bat out of hell even with the 3.31 gears. I was amazed how well it ran. Did not drive well though!! Front end needs work but shifted well and started right up.

Lawrence