When checking for a fan, look at the old Mister Gasket fans. I bought one in the package at a swapmeet for $10. It worked perfect for my engine. The pump was less than 1" from the radiator. The fan is flat on the front side clear to the tips of the blades. It's one of those stainless steel flex fans.
I had the same problem you are having, electric couldn't cool it, and it's just a stock 250-6. With the flex installed, it won't go above the 160 themostat, and does it ever move the air. I think it's 18" with out a shroud. I can bearly get a wrench to tighten the bolts. I had to tape the bolts to the fan and put the whole mess in together, thats how close it is. Joe
