Yes, the TR4 from about commission number 20694 and TR6 use the same seat runner. The early TR4 that used the same seat as the TR3 uses the same seat runner as the TR3. The TR4's that have the seat that lifts forward is the same as the TR6 and uses the same base that fits fine in the TR4 and TR6. I use TR6 seats in my TR4's. One TR4 is just under the commission number quoted above and the other one is about 14000. So I am guessing that maybe the holes in the floors are the same for early or late. I have a friend with an early TR4 ( with TR3 type seats)who just got a set of Miata seats and was working to fit one of them in the other day. He did not seem to be having any real issues in getting the one seat mounted. He has yet to permanently fit them into the car. In truth fitting holes in the floors for new seats is really no big deal. Just use a piece of metal (about 2 inches square) on the underside of the floor panel to act as a reinforcement for the nut underneath.
Charley Fitch
Maintenance Issues
