Identifying a 12 bolt rear end

[54belair]

With my recent purchase of a 68 project came a complete (but unassembled) 12 bolt posi rear end.

The only info I can get about the rear is that it was changed out because the posi unit "kept going out"

I have found both casting no.s and stamped numbers that are in the pass. side web or on the pass side tube. So far I havent been able to id the numbers.

If anyone can help---Id sure be appreciative!

Cast numbers are (in web) NF 3896838
stamped numbers are: HA 06 05 W 2
the stamped numbers are widely spaced in the order im showing

NUMBERS in the carrier are 326663 ngm51 c3

Ive looked for a data base that might show what the housing and center cection is from but havent had any luck so far.


Thanks for any help

[john]

I dont know if my book has a misprint or not but it shows code HA as a 3.07:1 for 64-66 and a 3.73:1 for 67-69. Probably not too much help.

[54belair]

I dont know John,

I was actually "thinking that it was 71 or later ?? due to the housing width and axle length.

The gears that were in the box withit are 2.83/1 (12 and 34)

If the guy had trouble keeping the posi together, I think I can see why with that ratio.

thanks for looking------- are you aware of a data dase with all these numbers in it?

[john]

Hard to say what you have, the 70 models and up used a three digit code.
The older two digit codes would have the shorter axles and housings. I get my info from the chevy pickup redbook 1946-1972 by Peter C Sessler.