Like the subject says, whats the difference between D100s and D250.

 

The D100 is a 1/2 ton...the D250 is a 3/4 ton...heavy duty truck. Typical differences between all 1/2 ton & heavy duty trucks.

Things that are usually different...and which tend to make the truck heavier in weight...
Stronger & heavier axle(s)
Stronger transmission
Stiffer & stronger suspension
Sometimes a more powerful motor
Sometimes a stronger transfer case (if 4x4)
Sometimes a stronger frame
W/D250/350 were avialable with the Diesel motor...and later CTD

A lot of it depends on what year the truck is, as to what was available & different.

 

trucks are 1984 D100 and a 88 D250.
Are the frames pretty much the same size and dementions?
Are the front control arms and sway bar system different between the two?