Have you test fitted the cab to the frame to see how much of a "hump" that you need?
You might be able to get away with making 3 cuts in the toeboard and bending the metal up to clear transmission. You can then weld up the pie shaped gaps in the toe board.
Then all you will need to do is massage the transmission floor cover to match the contour of the new shape of the toeboard and to clear the transmission.
I have done this twice. Once with a TH350 and once with a TH400.


1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission