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I am trying to organize parts that I will not be needing as I am doing a restomod on my 1959 corvette. Before I put up for sale, I want to get as much information as possible to answer any queries that come up.
Today I cleaned up the local areas where I expected the differential codes to be, and while I partially understand what I found, the stamping is not what I expected. On the left side, I found 3725899 and G179 right above it. I get that to be a non-posi rear end that was cast on July 17, 1959. To the right of the "GM", is 13 casted that I have no clue what that is (maybe the 13th casting made?).
On the passenger side, it is stamped (what I read as) "AB723" or "A8723". The 723, or July 23 assembly date, fits perfectly with the July 17, 1959 casting date, But I can not find what the "AB" stands for. I looked at 1959 gear ratio codes, and for a non-posi transmission, I only see AE for 3.55:1, AH for 3.70:1 and FJ for 3.70:1 with metallic brakes......but none of them have a curve on the right side of the second letter like I have.
Last edited by idcwmidi; Oct 29, 2022 at 09:08 PM.
The 13 is the casting number of the mold, nothing significant. The rear diff code must not be a Vette diff, but it is 1959 cast and build.
OK Thanks! I opened up my search wider for the 1959 year and found "AB" in the full size Chevy listings. It shows up as a 3.36 non-posi that came married to a powerglide.
So.....if that is true, I guess none of my drivetrain is original. The engine is SA code (1962 327) and the tranny is a Muncie (which was not available in 1959).
Now I have even less guilt about doing a restomod on the car.
Last edited by idcwmidi; Oct 30, 2022 at 07:54 AM.
Rear End decoding help
