Chevy 12-bolt identification

[GotGrunt]

Originally Posted by Baron Von Zeppelin

If it turns out to actually be 2.73 , then GP
there is a listing for it as 12bolt 2.73 non-posi = LE
12bolt 2.73 Posi = LS

10bolt ratio is 2.78

If it turns out to actually be 3.31 , then Buick A-body

LE is basically an "and/or" mystery code according to some Google searches.
Did find a few instances of folks trying to decipher ones they had acquired as loose pieces - and the above info is best data found.

in case you haven't tried the "turn test" on a non-posi ,
one revolution with lug stud - count pinion turns - then double that number.
1 and 5/8 approx = 3.31
1 and 1/2 approx = 3.07
1 and 3/8 approx = 2.73
etc ...

It’s in an old race car Chevelle so the guts have definitely been changed. I will know what’s in there once I get it out and crack it open.

Originally Posted by bbbentley

I had a 69 Buick Special, plain Jane 6 cyl. Made in Canada. It had a 12 bolt Chevy rear. The ONLY difference I could find between this Canadian rear and a Chevelle was the Chevelle casting is 3959038NF, the Canadian did not have NF at the end

It’s funny you mention that because this casting doesn’t seem to have the N or NF at the end either. I will double check that though once I get it out of the car and thoroughly clean off the housing. I wonder if all the McKinnon/Canadian Chevy 12-bolts were this way.