old trucks already have too much weight over the front wheels, nature of the beast but try not to make it worse.
while my 58 was designed for a v8 it did not like the 2 plugs coming out the back of the distributor
i fabbed a box to house the distributor and was also able to move my motor back an inch by doing so
i used a 700r4 trans also. my only interference was at the front 12'' of the floor
my 58 had a bellhousing hump and a flat floor over the trans.
i fabbed a trans tunnel to give me some clearance over the trans
not the best pic to show this but you can see what i did
everything was covered up by my consol
this may also fix your problem with the mechanical fuel pump.
if you can use it do so. electric fuel pumps are another fail point.