Need this Rear End - Decoded

This rear end is currently in a Buick, can someone please decipher and decode it for me. It is a 12 Bolt housing..... there are no codes on the axle tube.

Left side of pumpkin, just below diff plug reads....39439.



Bottom of pumpkin reads CFD 6



Top of the pumpkin reads BP



Thanks in advance.

---------- Post added at 08:43 AM ---------- Previous post was at 08:40 AM ----------

A few more pics....

 

Anyone?

 

I don't think those numbers are going to tell you much. You really need the code off the RH axle tube. It's there, you just can't find it! They are rarely where the books say they are, it could be on the front, the back, top or bottom, and close to the gear unit or close to the backing plate. You need to get a wire brush + mirror and go all over that tube.

---------- Post added at 02:44 PM ---------- Previous post was at 02:27 PM ----------

There are other ways to tell, you can measure the tubes, pull the diff cover, etc. The ratio is easy to figure with no disassembly.

 

http://www.jdrace.com/

Go to this guy's page, he has rear end identification page on it. And if you need parts or help, that guy is amazing. Knows his stuff really well and has reasonable pricing too.

He is Monzaz on the board.

 

Larry will be the NEW GURU soon.
Yes it is a 12 bolt olds rear

Casting could be the 394139 might have had the 1 not cast in...??? That would be a 31 Spline rear. 1967 1968 ratio would be 3.42 3.91 4.33 ish

Only way is to crack it open and look see. Jim

---------- Post added at 01:28 PM ---------- Previous post was at 01:26 PM ----------

There will be NUMBERS on the axle tube ALWAYS. Drivers side or passenger under front back etc. BUT they will be there. Keep looking if it really means alot to you.

Recover inspect removal will ALWAYS tell you what exactly the rear has in it. Years gone by gears break and things are replaced or swapped.