[TR] Trunnions later TR4 with 3 degree caster

[Randall]

> Its my recollection that TR2-3B and probebly early 4 vertical 
> links also had a finer thread and more of it than the later 3 
> degree links on 4A and 6's.

Not sure about the thread pitch, but the length was definitely longer on TR2
through the end of TR4 than on 4A through 6.

>  As far as the left and right 
> hand threads goes, I have a pair off the car and on the bench 
> and if it will help, can let the list know which thread goes 
> on what side!

The threads remained the same on both sides through the end of TR4.  The
trunnions were "handed" due to the angle between pin & vertical link; but
the links were the same from side to side (hence the threads were too).

Randall