Hi Ian,
I think that fit should be pretty tight with new parts. For one thing the soft brass of the trunnion will to some degree conform to the steel threads on the v-link. Plus it will all function differently once the car's full weight is back on the ground. (That's really the only time you can judge if the steering is binding.)
Be sure to use some 90W gear oil in the threads during assembly, both to lubricate it now and to make it much easier to squirt in some grease (or more 90W gear oil if grease won't go it) later once re-assembled. I.e., don't assemble these parts "dry" and try to lube it after assembly. (Re-reading your post, it looks like you are already doing this.)
It might be possible to "lap" the parts together, but I think I'd rather have them a bit tight to start with, than at all loose. I'd also be very worried about doing any sort of abrassive work around the acme threads, since it would be very difficult to be sure any and all traces are cleaned out, and any little bit remaining in there after it's all reassembled would continue to abraid and quickly wear out the parts.
I recall it is also very easy to screw the v-links into the trunnions too far, and thus get some binding when the male acme threaded portion of the v-link bottoms out in the female threaded hole in the trunnion. In other words, if it's threaded in deeper than was ever intended, iot will bind.
One reason this happened with the parts I was working with was that the replacement rubber dust/grease seals I got seemed quite undersize (perhaps there are more than one type, some of which I am just not familiar with). Because of this, it appeared I needed to thread the trunnion in further, since there was still an obvious gap at the seal.
The last time I did the job I carefully rebuilt one side at a time (1st time it had ever been disassembled, judging by the ancient bushings in there), and this particular question is one reason I'm very glad I left one side intact, for reference.
I forgot to measure the length of the trunnion/v-link assembly before taking it apart. So, I quickly checked the other side found I'd screwed the v-link in one or two turns too far, fooled by that ill-fitting seal! (I also had the benefit of a second TR4 frame sitting nearby awaiting disassembly, mostly stripped, but that still had what appeared to be the original front suspension intact. Measuring this 2nd set also helped confirm the correct dimension.)
It's been a while, but I'm fairly certain I measured the combined height of the two pieces to be almost exactly 11" from the very top to the very bottom (not counting the grease zerk). Yes, the measurement varies a lot depending upon exactly where you put the ruler or tape measure, due to the shapes of the pieces. I was just using the most extreme edges of each part. The trunnion threads are so coarse that being a single turn too tight or too loose makes quite a noticible difference in overall length. (Measured "length" would be vertical/top-to-bottom, if the parts were actually on the car.)
Once I had set the assembly adjusted to the measured length, I found there was quite a gap in the brand new dust/grease boot I'd installed between them. That meant taking it all back apart and improving the boot with a secondary seal on top, then putting it all back together again.
Regarding your other question, I don't have the numbers handy, but the factory service manual shows the adjustment of the steering stop in total degrees of turn for both inside and outside wheels/tires (they are different). On my car I just removed the stops or left them loose until assembly was far enough along to test fit a tire and wheel, then turned the steering fully one way and fully another, adjusting until there is no tire or wheel interference with any other part of the car on either side. Also check that neither the brake hose or the tie-rod appear to be over-extended at full turn. Do this with wheel and tire temporarily mounted, but the springs and shocks not installed, so clearances can be checked all throughout the up and down range the suspension, from upper to lower stops.
Not very "scientific" I know. But the supension on my car is pretty far from stock now, so the dimensions in the service manual mean little and I know I had to fabricate stops that were slightly larger than original.
Hope this helps!
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