Decode 12 Bolt Rear End

Need help to decode 12 bolt rear end. KD 1 OO 9B is stamped on the p***enger side axle, 12345 is stamped to the left of the 12 bolt cover and 1278 is stamped to the right of cover. I removed cover and counted gears (41-7) 5.86 ratio. Would like to know year and what it came out of.
thanks

 

Hmmmm...


Those rears were available in...


Chevrolet 64-72
Chevy II 64-72
Chevelle 64-72
Camaro 67-72
El Camino 65-72
Firebird 67-72
Grand Prix 70-72
GTO, Lemans 65-72
Monte Carlo 70-72
Nova 70-72
Olds F85 68-70

Not sure yet what years that gear set was available for. Are there numbers on the gear housing?

 

I s****ed more grease and found these numbers in the front and right side of gear box. 3959038N and the left side in front was GM 54. If I read them correctly.

 

Time to make a decision. If you're going drag racing, keep the 5.86 gears. They were put in there by somebody other than the factory. If you want a street gear ratio, time to spend gear money.
If the previous owner has thrashed and trashed it, all you have is a donor housing that fits A & G body GM's.

 

hollander shows

kd

was a 1968-1969 or 1971 chevelle rea with a non locking 2.73 ratio

 

a bop gear set will not interchange with a chevy 12 bolt

 

Is there anywhere online to decode 12 bolt rear axles?

 

the ****er-dana website has a search function by bill of materials markings (they tell you what to look for) and most muscle car sites have code numbers for the brand. I googled for axle codes and came up with a couple of options.