Hi Ripper,
There are so many things that cause vibrations, you usally have to do it by process of eliminationif there is nothing glaringly obvious.
Some things I have found to check are, Diff and gearbox yokes tightened to the correct torque, uni joints,
slidingspline on tailshaft, g'box and engine mounts, out of round or out of balance wheels, missfire in engine at higher revs, uni joints not properly aligned if siding spline has been taken apart. Not sure if this
relates to a TB42, but I've seen the rubber in the harmonic balancer go soft on a car and cause the
outerpart to wobble and cause a vibration at certain revs.
Also check your viscous fan hub and water pump for any wobble or freeplay.
I see you are looking for a wheel brace, I bought this one the other day from Bearing Service in
Brisbane.
It is a Toledo brand tool.
Cost me $35.
As you can see it folds up and can be adjusted in lots of ways.
Also has the half inch square to fit any size socket.
Much easier to store than my old fixed cross one.