[5.9 Cummins Fan]

you usually wont find gauges that fit in OEM dash holes...good gauges like autometer, isspro etc have to have custom mounts. I did it on my 92 by making a dash out of diamond plate aluminum and cut holes for the gauges, not too much work IMO

 

[5.9 Cummins Fan]

I think isspro makes one that will hook right up to the existing wires. My autometer just works off the alternator...never had trouble with it. Im partial to autometer though and try to steer other gearheads that way too. Hope that helps. You can get a bigger one from autometer too, so you can just cut the hole in the original dash bigger to make it fit.