http://67-72chevytrucks.com/vboard/s...d.php?t=663780
This thread has a good shot showing the Pacific Fab cross member with the factory AC compressor. I couldn't find a matching pic of the Dirty Dingo setup. My recollection is that they both put the AC in the same place...especially if you're keeping your t-case in the factory location.
I know some guys have made it work by making or using fancy right angle fittings on the compressor. Or they move the driveline forward so the AC sits in the flared section of frame, but that will require moving the trans/t-case cross member and making new driveshafts.
Hopefully someone will chime in with personal experience.