I have a 235 in my 52 with next to no clearence. I actually had one blade fly off and land on the crossmember. I was running about 2500 rpm when it happened and it twisted the belt but somewhow did not even scratch the radiator.
I was only about 3,000 miles from home at the time. I used a hacksaw to cut the opposing blade off. with a two bladed fan I was able to get to where I could find another old one with no problems.
If you keep the setup you have you may want to check your fan for cracks, mine had had one blade cracked through the rivets for a long time apparently.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-