I want to remve the ac compresor. 3.9 litre. Does anyone know what serpentine belt will work, the one the books say will fit 3.9 with no ac are too short.

too short? the only difference between a dak w/ a/c and a dak w/o a/c is the compressor and obviously the belt. are you sure the belt is really too short?

All I can think of is that there were Dakota's that didn't have A/C or power steering. So, if you have power steering (I don't know who would have bought a truck without power steering), make sure it's a belt for power steering, but without A/C.
Also, what year is it?

yes it is too short. i released the tennsioner as far as it would release and can't get the belt on. Guess i will have to measure it to get the length.

If you run to the local parts house, they have this handy lil deal with a round cap on each end that will tell the exact length of a belt.. now take a string or thin pliable wire and wrap it around your intended belt path... subtract approx ONE inch from total length (not folded) and that should be the appropriate belt to get decent tension without a major grunt of install. I had the same problem ditchin the A/C on my 92...