The 235 in my 49 gives me about 1/4" clearance between the fan and the rad. It has been that way for about 15 years and my biggest concern is changing fan belts.
The pump I have has an external impeller which goes into a hole in the block. My concern about changing to the other style pump with the internal impeller is whether or not the fan belt will line up.
I looked at a pump with the long shaft and considered pressing on the hub farther and cutting the shaft as you suggest. However if I recall the longer shaft pump also has more of the pump body casting surrounding the shaft.
