A little more info:
FAM 1718 is the semi-flexible joint and is standard on Triumph Vitesse, Herald, Spitfire, GT6, Dolomite, and other models.
145377 is the forged ujoint standard on the TR5 and TR6 and listed as a suitable replacement for the TR4 and 250. It is also listed as an upgrade for the Triumph Vitesse and Herald so the ends are correct to replace the FAM 1718. I'm guessing it isn't listed as a replacement for the other applications for the FAM1718 due to the slightly longer length that is not accomodated by the other steering column designs.
145377R is a stamped steel version.
The TR7 uses a joint but the intermediate shaft is integral. I'm guessing the pinion size on the rack is still the same as the spitfire.
It appears the bolts are not included except for the rebuilt unit and may have an odd pitch from metric or sae. I have the fam 1718 joint and don't know if the bolts are different on the 145377. I wouldn't drill and retap as the bolt shank fits into a notch in the shaft and pinion.
thanks, great info. i need to make up an intermediate shaft for a custom build to fit an aftermarket column. so i would have to have a Triumph steering shaft with the correct spline to make the intermediate shaft.
it would be much easier if a Borgeson joint would fit. then i could get all the rest from them too. i may just order theirs and see if it fits. i can get it with anything i want on the other end. i'll report back what i find out.