Thanks for the articles, JD & Joe. They were very helpful.
Certified, the problem is I had trouble adjusting the turning resistance on the pinion (2lbs at 8"). I could only get it too loose or too tight. My car had been hit in the driver's side front corner which could have bent my rack a little. When I took the rack shaft out, it was bent a little and I spent a lot of time trying to get it straighter. When I finally decided it was as straight as I was going to get it, there ended up being two places somewhere in the middle of the travel where the pinion seemed to be too tight. I'll know more after I put the car on the road but I think it might affect steering effort when driving. If so, this is most likely because of my efforts to straighten the rack and not from any accident damage.
There are less than 20K totals miles on it so my thought is a good rack shaft should allow me to fix my problem if I have one.
Alex, the article JB posted has a table that gives specific information about Triumph steering racks. The for Spitfires and Heralds is paraphrased here (the table has more detail):
Model | Rack shaft part # | Rack length (mm) | Pinion teeth
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GT6 | 208058 | 660 | 7
Spitfire 1-3 | 208058 | 660 | 7
Herald 1200 | 208058 | 660 | 7
Herald 948 | 208058 | 660 | 6
Before I wrote this, I had only looked at the pinion teeth after reading your post so I became aware that there were two different Herald pinions but I didn't realize that they both were apparently used on the same rack shaft! Hmmm....
I am assuming from the table that all the Spitfires had the same rack because there is only one entry for them and because there is only one for the GT6 and it's production ran from '66 - '73 but the "1-3" designation baffles me.