I was a Jag mechanic (and several other "foreign" cars)way back in the day and personally think the SU carb is the best ever made.
After seeing this thread, I went out in the shop and looked at the '48 2 ton. There is certainly enough room for 3 SU's with a well made manifold. Might have to be creative with the air filters, but inner fender and steering clearance is there.
This one has currently has twin W-1's on an Offenhauser manifold.
