This may have been covered already, but since I wasn't able to find an answer I'll ask anyways. The tranny in my 74 is quirky, sometimes it'll shift beautifully, othertimes the engine rpm's will go up to 3500-4k and the acceleration doesn't change one bit. I am thinking that the torque converter is going bad. If it is I was planning on putting a rebuilt tranny in with an added 4th gear. Can you get an fmx kit/ tranny with 4 gears or would it be better to get an aod or c6 with a 4th gear? I realize I would have to change cooler lines, tranny mounts, etc. to do this. If it is possible to get a rebuilt fmx with a 4th gear installed, where can I get one. I haven't found a place to get it yet. Any help would be appreciated.