pretty sure crown vic is a 44 but dont hold me to it.
i just did what you did. but i scored a set of ZJ backing plates at the same junkyard i got the axle from.
after that i got new zj calipers/pads/rotors. and then i got the rubicon bearing retainer, JEEP part number
5083678-AA
get TJ rubicon bearings and seals. part number
CRBR10 and
CR18731
you have to open up the zj backing plates a little, the hole is too small to fit the 44 shafts and bearings through. i used a large dremel-type tool. make sure you open them good enough, otherwise they will catch the seal and leak(happened to me, not fun)
next i redrilled the xj 44 axle flange to the zj/tj bolt pattern.
next i got some longer studs and grinded one side flat, and used those to hold the backing plates and bearing retainers to the axle.
next i had to get 81-83 mercury cougar lug nut studs. the stock were too short. part number
9210075
after that i bled the brakes and all was well and good. it was quite an upgrade from my stock 27 spline 8.25 that was leaking into the brake drums causing the pedal to goto the floor.
you may want to use an upgraded proportioning valve. i havnt, but it is my next upgrade. also, i was able to sell the stock drum brake backing plates and such for about $50. they were in mint condition. overall i totalled everything up and i am about $500 into the axle. next comes an aussie.
good luck