That goes for the later shells as well, the tunnel-hump covers the surgery required to fit the floor shifter. I suppose with the rods going forward, there might be a tad more room, but like you say, probably Not in the Early A's
Rusty, years ago I was a transmission rebuilder, and I think that you will agree that, while the A745 might fit into the Early-A tunnel, to try and make one live behind a 408, per post 26,will be pointless.