I've got a 67 lwb in case the screen didn't clue you in

that has a saginaw 3 speed on the column. I can get a close ratio 4 speed, pretty sure it's a muncy, not sure what it's out of. will this be a direct bolt in? well I am pretty sure it bolts right up to the bell housing, I guess the better question is, is it the same length as the 3 speed? or will my drive shaft have to be shortened? Any info on this will be helpful. Especially from those of you who have made a swap like this. Thanks
Ean