If the differential is 6 lug, I'm guessing late 60's, 70's 1/2 ton 12 bolt.
Looks like quite a few leaf springs have been removed, probably to soften the ride.
Also, it appears that the stock rear engine mount/crossmember has been completely cut out. Some reinforcement in that area may be prudent as that crossmember
tied the frame rails together at the front spring rear shackles.
Neat truck !
