Hi Folks!
I am planning on using a 4hu out of a xj8 in the back of my project (not a jag) can someone tell me if the newer 3rd members still have 19 spline stub shafts? I know on the older inboard brake diffs a dana 44 lsd carrier can be swapped in. and I'm looking to do that on the later one if possible, but I can't seem to find any info on the later units. they have 4hu cast onto the top, so at least I think I have that nailed down. also, this will be living behind a stout small block chevy (approximately 500 crank hp) so also looking for input on what the weak points of these diffs are. The axle shafts will not be upper control arms, if that matters. any help would be appreciated! thanks folks!

 

well ok developments, per the workshop manual, its a 14hu, so, anyone care to shed any light as to this particular differential's dimensions etc, or possibly point me towards a workshop manual?

 

The 14 HU diff has 25 spline output shafts.

The Crownwheel is only 8 inches vs the older 15 HU and 4 Hu /Dana 44 units 8.5 inch diameter.

On a supercharged AJV8 (around 400 bhp) they're marginal. Many have proven to be ok but they can fail. They fail by the teeth of the pinion shaft fracturing off. They're not as bad as some of the GM ***** out there- like the 2004-2006 Caddy CTS and their 7.6 inch Getrag rear ends, or the infamous last gen firebird GM 10 bolt fiasco, but this is a Jaguar!
I personally wouldn't use it for your application. For my Jag- I adapted an earlier 15 HU unit (the XJ40/X300 style without inboard discs) and used reinforced Dana 44 ring gear but also designed and built reinforced input flange and 30 spline output shafts.
This gives me additional confidence. The nose of the hogs head of the 14 HU is on the centerline of the driveline and the nose of the earlier 15HU is slightly offset.