Alan,

Ideally, yes, you need a pair of "V" blocks, about 50mm size will do, or any size you can borrow. Or, you could make a pair of wood packing pieces to support the diff unit with its bearings fitted like this picture:-




I did my RK like this and got good results.

I assembled diff into the axle casing without half shafts or torque tube and used a dial gauge through the aperture for the torque tube. A bit fiddly but seemed to work OK.
Need a dial gauge with a 'finger' rather than plunger.

Location: Melrose, Scottish Borders

Oh! of course how stupid of me, pack the blocks with a piece of wood, why didn't I think of that? I have a lot to learn.

Location: United Kingdom

THanks for the suggestion Jim, Mine has a plunger so I think I'll go with Bryan's solution.

P.S. I'm going to come to Wooler on the 14th I'll see you then

Location: United Kingdom