The 5 speed std would work with the bellhousing that you got with the 292 from the '65 (presuming it was std shift) and would be a lot easier to mount this bellhousing into the '46 Truck. The trans will hang from the bell and you can just make up a driveshaft. I believe the overdrive is .73 to 1 so that will definetly help your rearend gear ratio be a little more driveable.
