[midniteblues]

G.o.m is right.
It can break the ears or crack the bell if the correct sized hole isn't used also it can wear out the pilot bearing/bushing quickly.

Also can cause a lot of run out in the clutch disc witch in turn will wear out everything quick.

G.o.m is also correct about the 67(and earlier) bell having the smaller hole.

It's not advised too use a bell mounted too the bell crossmember and a tail shaft mounted crossmember together. It's too ridged and may break something.

Some 4spds use a shifter body mounting plate.
Some of these can be modded to move the shifter slightly forward too give a lil' more seat clearance.
But with a muncie reverse is in the tailshaft so this may not work.

I would certainly try too use that shift handle seems too be the way too go.

Floor mods are pretty much a hole cut into the side of the hump. You could buy or make a small box too keep a flat spot for the shift boot but you gotta decide what interior flooring your gonna use and mod it too fit your "box".
No high hump is nessacary.