Unless you find a trans out of an F-1, either the "light duty" 3-sp or the HD 3-sp, major surgery is required to the crossmember. The versions of the HD 3-sp that were in F-2's and F-3's has a different rear mount to match the different crossmembers used in those (see below). Likewise, the "SynchroSilent" 4-sp used in the bigger trucks (F-4+) will not fit the F-1 crossmember. No modern 4-sp's will fit either. Once you decide to cut the crossmember, all kinds of possibilities open up. If you cut it, you need to restore the lost structural integrity.
The 48-50 LD 3-sp's and 48-52 HD 3-sp's were floor shift, 51-52 LD 3-sp's were column shift. HD 3-sp's are pretty rare nowadays, as noted above.