First off, it wouldn't be a Dana 30 rear, it would be a Dana 35 rear. But the Dana 35 and the Chrysler 8.25 do look a lot a like. I thought I had the 35 in mine until I went to replace the rear wheel bearings and the ones I got were too small. But like Jim said measure the tubes, the Dana 35 has a 2.62" tube, and the 8.25 has a 3.00" tube. Here is a link from another site that shows the 2 side by side.

http://www.rocklizardfabrications.com/C_8.25_Picture.jpg

99 XJ Sport 2 Door, 4.0L, 5 speed, all stock. Daily Driver
79 F150 Standard Cab Short Box, 400ci, NP435, NP205, 35" SSRs