Identification of parts

[gordy]

I recently obtained a '39 Chevy body and frame onto which a previous owner had installed a front suspension clip and rear end reported from an F-car. I am beginning my "street rod" project, and would like to identify the year of manufacture of these parts so that I may obtain the correct replacements when I refurbish the bushings, bearings, brakes, etc.
All I have to go by so far are the numbers on the differential unit:
On the right side axle tube front is what looks like "FJ G 8181 I", but as usual, these are about half-stamped on the tube. On the center web is GM21 and on the other side F 268 or 288. Also cast into the center is 125433 or 125488 or something like that...very hard to read.
The rear drums are finned, the steering gear is in front of the crossmember.
Can anyone help define the year?
Thanks,
Gordy

 

[Eric]

"PJG"- not "FJG" was a common 2.41 rear axle for 1971-1977 F-bodies- that being so, it would be an 8.5" ring gear 10-bolt. Virtually all GM RWD vehicle rear drums were finned, and the other numbers don't mean anything to me (not that they don't mean anything- I just don't have a reference for them). In any event, for brake parts- the parts used on that 8.5" rear were also used on a pile of other GM platforms from '71-80- including 'B' bodies (Cadillac Devilles, Pontiac Bonnevilles, Chevy Caprices) and '74-77 'A' bodies (Chevelle, Nova, Grand Prix, etc.). As for the front steering- more information than the box/gear being in front of the crossmember is required. Take pictures and post them if possible.