apparently my speedometer cable is not compatible with the new full gauges and the parts store has several anybody know which one is correct

 

With every pre-'97 swap, from idiot lights to gauges, you will need a new oil pressure sending unit and a coolant temperature sending unit.
'84-'96 Oil pressure sending unit is Mopar #56026779
'84-'96 Coolant temperature sending unit is Mopar #56027012
'97-'01 Oil pressure sending unit is Mopar #56031005
'97-'01 Coolant temperature sending unit is Mopar #56027873

'84-'96 Gauge clusters look very similar, but the main difference is the speedometer cable.

'84-mid '87 and mid '87-'90 use two different speedometer cables. If you're swapping gauges from a '84-'90 XJ, you will need to get the speedometer cable from the donor vehicle.

Gauge clusters from '91-'96 get input for the speedo electronicly.

Clusters from '97+ XJs are also completely electronic, but different from all others ('96 and older).

So... '84-'90 are interchangeable (as long as you get that speedo cable!). '91-'96 are interchangeable . And '97-'01 are interchangeable (also interchangeable with '97+ Wranglers).