3 spd swap to 4 spd possible???

I just got a 64 Dart with /6, 3 on the tree and want to go to a 4spd. Will a late model od 4spd work? and if so, what tunnel mods do I need to make? I was wondering if I could just cut whatever hole is necessary and then make a sheetmetal surround to mount a boot too. Or is the shifter somehow mounted to the hump?

anyone know the hole dimensions for a 4spd shifter and where if needs to be located?

Will the 4spd bolt to the 3spd bellhousing?

Thanks!