the box design appears unchanged from MKX up till probably when LR went to rack & pinion
( if they have). Even Land Rover Discoveries had the Adwest box, as well as Defenders
One of the main gear parts differs for each application (even in each Jag)
Each case also differs
In the case of 420G, there is NO alternative, as the mounting system is of the utmost restrictive and stupid design. ( the entire engine bears down and is involved in the mounting)
The MKX (and others) mount directly to the main suspension I-beam, and are somewhat amenable to adaption…ie a Burman can be replaced by a Adwest
A cursory examination by me indicates not all Landrover casing bolts are in the same plane, however, I need to examine one in my hand, which I have been unable to do
The seal kits are the same