Anyone ever bagged or know about the jaguar xj6... not sure exactly what year... think its an 85

What was done, or can be done... I suggested using a truck axle... Any advice?

Well I'm not much help but I can tell you I have one!! (same same) and we are doing a whole rear clip to suit it.... There are quite a few people on here with IRS setups - it would be worth you doing a search for topics regarding it as there are a few that have photos of their setups

Thanks

i think Seth (twisted minis) did one on a crown victoria

From my understanding those rear ends have limited suspension travel capabilities.  Could be a good opportunity to do some kind of cantilever bag setup.