I put a 350/TH400 in a '49 3100 and had to make 3 cuts in the toeboard, then peel the sheet metal upwards to clear the transmission.
This created pie-shaped gaps, so I cut some pie-shaped patches and welded them in the gaps.
I then beat on the transmission cover until it conformed to the new shape of the hole it is supposed to cover.
It went a lot easier than I expected, and once the floor mat is in place, you cannot tell that anything was altered.
