ent72olds

Gentlemen, I have a 12 bolt, bolt in axle rear laying in the garage, and was hoping someone could ID it for me! There is a stamp on an axle tube that reads R6.....on the center housing, there are four stamps! One reads CFD 3, another reads 307, another reads 402227, and the last is a big "P"....
Any help would be greatly appreciated!

442Cliff

The R6 on the axle tube should be the code that is key. I know it is not a 1970 rear. The only R codes in 1970 were R2, R3, RA, RB, RE and RF.

ent72olds

Thanks Cliff, it's a start!

1969w3155

R6 is listed as an open diff. 2.56:1 on disc brake equipped cars for the years 1967, '68 & '69. (O-type '68-'69).

jensenracing77

i think that would be a 69 2.56:1 open rear end with 12 bolt cover 10 bolt gear
"O type". my info only shows the R6 in 69 but my info is not near complete.

jensenracing77

lol, you got me by 2 minutes

1969w3155

I have had that happen to me also, by the time that I am done typing and/or researching, someone beats me to the punch! I got my info from Supercar Unlimited.."442 by the Numbers".

ent72olds

Thanks so far guys! Great work...any way to know if it would be a direct bolt in to an A-Body by that info? Would it be worth rebuilding, and any advantages over my 10 bolt ? Thanks again!

1969w3155

Yes, that is an A-body coded rear axle.

ent72olds

Thank you!

507OLDS

The 307 is probably the Julian date,meaning it was cast on the 307th day of the year.This rear will have the sealed ball-bearing style axle bearings,with the seals pressed into the axle tube.