Measure the opening in your fan shroud....if the first fan you posted is 19.5" in diameter, then you need to have 20.5" of diameter for the opening in your fan shroud. Make sure your motor mounts aren't rotten:grin: Why are you in such a hunt for a 7 blade fan? The 5 blade fans work fine with a healthy cooling system.
I measured the shroud not the fan. ou: But its 22'' opening of the shroud so that would mean I have a 21'' fan. Right? o No: The motor mounts aren't rotten. Who says my cooling system is healthy? :laugh: I want to cool the motor more and do not want any cooling issues. Also another option to check off the list. :Brow:
make sure you dont just measure one spot ... some times a little oblongness(<---i made that word up) can give you an incorrect reading. :shock:
Yea, I got 22.5 from top to bottom and then got 22 from all the sides weather I did it from the inside to inside or outside of the shroud.
I did briefly talk it over with Rick Martinez to see what setup he uses. He has a 7 blade fixed fan and the temp stays at 190-200 when towing in the heat. I'll look it up tomorrow in the '72 and '73 service manuals to see what the H.D. cooling might have consisted of.
