The bracket arrangement was the same until part way through TR6 production when there was a rear coil spring change. The difference between the brackets is the relationship between the mounting holes to the chassis and the holes accommodating the trailing arm support bolt. These holes are displaced up and down differently on each bracket and in production provided the correct camber when fitted in the relationship shown below. When setting the rear suspension start with the correct parts for your car then measure the camber. Fast road cars are likely to be set at 1.25 to 1.5 degrees negative. To change the camber the brackets can be mixed and matched, even turned upside down to get the correct setting. Bear in mind that the chassis may have been repaired and the mounting holes may not be exactly in the correct position. Check what brackets are fitted and order extras of the ones you don't have so that you can test various combinations. We cannot comment here on what the outcome will be as the choice of brackets will depend on individual chassis and spring combinations.
Whilst going through this exercise, the ride height from one side to the other will change. This can be corrected by using Superpro spring insulators SPF2327K or SPF2327-5K, which is the same part, 5mm thicker.
Brackets available.
141399 1 Notch New or 141399SH 1 Notch Second Hand
141398 2 Notches New or 141398SH 2 Notches Second Hand
155502 3 Notches New or 155502SH 3 Notches Second Hand

Note: - In the standard fitment (below) the notches are upper most.
TR4A-IRS, TR250, TR5 TR6 up to CP52867/CC61570 INNER 141399 (1 notch)
TR4A-IRS, TR250, TR5 TR6 up to CP52867/CC61570 OUTER 141398 (2 notches)
TR6 from CP52868/CC61571 INNER 155502 (3 notch)
TR6 from CP52868/CC61571 OUTER 141399 (1 notches)