235 in a 63?, or was it a 230?. The 235's run ended in '62, the physically larger 230 was intro'ed in '63 and will require modifications to fit into the '46 engine bay. Not a direct bolt in. The fully synchroed "Saginaw" 3 speed made it's debut in trucks in '67 behind V 8's only, while the sixes retained the old "Muncie" thru '68. In '69 and up all trucks got the "Saginaw". However, I dont think you can use them unless you change the rear end, as the '46 will have an enclosed drive shaft, not compatible with the later tranny. Not trying to rain on your idea, just make sure you know what you're getting into.
PS I think there may be a bell housing issue as well, as the '46 will have the floor starter switch mount at the BH also? Not alot is direct bolt in compatible from '46 to '63 up when it comes to driveline(unless you change it all from the bell housing to rear end)
