3 speed toploader to 223

[TKEBH964]

I have a 58 Ranch Wagon with a 223.  Currently I have the standard 3 speed with no overdrive. 

My transmission started leaking around the input shaft and my clutch is on its last legs.  I am dropping the transmission soon to replace the clutch, and I am debating wether I should fix the leaking input shaft or find a toploader so I can have 1st gear syncro.

If I go for the new transmission, which cars would have had the toploader 3 speed?  Also, when doing the swap to the toploader, what do I need to watch out for?  Is the mount in a different spot?  Will the new transmission be longer, will I need a new driveshaft?

Thanks for your help.

[SkylinerRon]

63 and newer full size. May need to change yoke.

Ron.

[4banger]

I have a top loader 3 speed syncro out of a 67 ranchero.