I changed from the crash box 4 speed to the regular 3 speed in my '48 F-1. What a difference in drivability!! If you go down this route be aware that the driveshaft, rear support and u-joint are different. Everything is readily available from the usual vendors except the driveshaft and yoke. I found mine (with yoke!) leaning against a barn in Maine!!
True, though there is a 3 speed "heavy duty" which uses the same yoke/driveshaft as the 4 speed. I have one waiting to go into mine. Can't wait to make the swap.
