In '66-'67 Ford made a trans called the "MX". I've never heard of the "FX" in Galaxies before (but, that's just me...). The MX is VERY strong, has an 11" band for 1-R gears. It often was equipped with higher-speed-stall torque convertors for that "jetaway" takeoff performance. These torque convertors 'lock' at 1500 RPM instead of the usual 1100 RPM. It makes for a real quick, effortless feeling when driving, but at 55 MPH (2.75 rear) it gets worse gas mileage than at 65 MPH because the convertor locks at 58 MPH!