The tank is unique to this model. There was one on eBay here a while back and I am still kicking myself for passing on it.
Rods are similar to, but not the same as Square four.
There are a couple of different cranks - well, flywheels - in the cast ion motors. One quite a bit heavier than the other.
The dive side crankcase was prone to cracking and might be hard to come by.
I remember reading that Ben Mitchell converted a KH head to twin carb. That would have been interesting to see.
'51,'56 Squares, '48 VH, '27 Model C, R67/2, Mk IV Le Mans, '06 Super Duke and Ariel projects.