I suppose anything's possible, and I've seen some really creative substitutions over the years. But the presence of an adjuster is a bit puzzling, since the TR7 didn't have them!? According to information I have, the TR7 five-speed and the TR8 had 9" x 1.75" rear brakes, which happens to be the same size as those for the TR4 (although I'm pretty sure all were Lockheed on the "wedges")