Will a 1989 dodge truck body fit a 1996 frame

Those are different generation pickups so it won't be "bolt on". If the wheel bases are real close it should be possible if you can fabricate body mounts, do electrical etc.

Without much modification, I doubt it. The 1994-01 Rams are a wider truck overall, and the driveline is different as well. Besides the mounts, and the clearance issues, you would need to modify the transmission tunnel on a 4x4 to accommodate for the newer Transfer case. The 4x4 lever is on the left on the 94-01, and on the right side of the tunnel on the 1972-1993 Dodge trucks. The frame used in this generation dates back to 1972, with some minor changes in 1974 for the now frame-mounted "side saddle" fuel tank. I would look for a nice 1974-1993 Dodge D/W Series (RAM) truck frame. It would be much less headache than trying to modify that 96 frame.

Also, any year from 1974-1993, the parts will bolt right on. 1960's and prior are too narrow, and 1994-01 and newer are too wide.

I measured the frame on the back and they're the same withd, what else is different?