Fred and Ed... he is describing a 3sp Muncie 318, not a 420 4sp. It has a synchronizer drum which is no longer available anywhere but used or NOS (if you are lucky enough to find one.) Some of the usual vendors stock replacement brass synchronizer rings so that issue is repairable, as long as the inner gears are not worn out.
When I visited the Novak site I did not find anything for a torque tube 318. Don't know about Anaheim.