There are a few differences between the RX-7 rack and the Miata rack. First of all to get the retaining cover off the end of the rack, instead of punching the retaining ring out like for the Miata, simply rotate the cover counter clockwise to remove the retaining ring that holds it in, it’ll come out of the slot on the end of the rack (the cover has a groove in it that you can use to spin it). Secondly, there is no supporting barrel in the middle of the shaft (or at least it didn’t come out of mine). The rest of the procedure is exactly the same for a Miata and an RX-7.