Are all SM420s interchangeable? Specifically, can I take the main and clutch shafts (with all their gears and synchros in place) from a '49 unit and swap it into a '52 case (keeping the idler and reverse idler gears and shafts in place)?
And what's the difference between the 50-60 models and the 10-30 models? How can you tell which one you have?
Thanks,
John
