A855 - 5 Speed

I won't be returning to stock, and I would be willing to cut the original 4 speed hump out (and stash it away with everything else original) however I'd have to get rid of the bench seat.
I like my bench seat, it's amazingly comfortable and I like the look, I didn't even know a bench seat was a thing in a 67-69 Barracuda before I saw mine for sale.
I'm a little attached to it, and the 4 speed doesn't bother me on the highway, but a 5 or 6 speed would make it 'complete' in my mind (that and power windows, ha!).

Got the efi, swaybars and junk already, maybe, some day, I'll ditch the bench for some modern seats and a 5+ speed.
Is there a list I need to be on somewhere?
Could the under side of bench seat frame be modified to clear a larger trans tunnel? I saw a build on a vintage Chevy truck where they put in over drive trans and modified bench seat frame to clear the bigger tunnel. Might also be able to put spacers between seat and floor raise seat a tad to minimize seat frame mode.