'69 Barracuda T56 swap, floor, cross member

How far back is needed for that shifter/hump?
Is it possible to measure from the floor/firewall seam, or maybe I missed that in this thread.

I have a bench seat 4 speed, I know the bench will not work, but it would be nice to know.
No plans to remove the bench, it's actually extremely comfortable, and the kid wants it to remain too.
Tunnel is tall all the way back where that side to side hump is in the floor. A TKX is a lot smaller. Yeah may be able to modify bench seat frame to clear the bigger tunnel.

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