M1008 are the Chevy one tons, M1009 are the blazers, both come with a 6.2 chevy diesel. blazers supposed to be 3/4 ton, don't know for sure. I'm not even sure what axles are in it, or the gears, I think they are 10 bolt, but not sure.
Have had a hard time finding a specifaction sheet on this one I have.
M1010- 1 ton pickup chasis, 6.2, th400, NP208, 4.56 gears, detroit in the rear
M1028- 1 ton pickup chasis, ambulance box, 6.2, th400, NP208, 4.56 gears
detroit in the rear, rumored that some have limited slip in front
M1031- 1 ton 4x4 pickup, dually, 6.2, th400, NP208, 4.56 gears, detroit in
the rear, True-trac limited slip in front (this is the rarest one to find)
The military versions came with black out lights and were all rated at 1/4 ton heavier than their civilian counterparts. It is unknown to me if the militay actually used heavier duty springs to up the capacity. All of the M1008's I have seen had the exact same spring packs as all of the K30's I have seen. However, the spring rate itself could have been higher(in the CUCV's).