Cool looking truck. Your tranny appears to be the old 4 speed "crashbox" type. Gears are non-synchro. You can update to a synchro (sm420) but you'll have to change the bellhousing because the bolt pattern of the 4 tranny mounting bolts is different. You may or may not be able to keep the partially enclosed driveshaft setup, not sure about that. 'course you could find another crashbox to put in there, it's a good unit if you don't mind double-clutching.
