It all depends on the shroud and how much of the core the fan can pull air through or push through. No fan will work very good if it only moves air through a portion of the radiator core. The electric fans that really work good, pull a lot of amps and pull air through the whole core. F*rd used a very good fan on the Crown Vic's, if you can find one in the pick & pull, you could save some money. I believe these are the dual speed fans. Be sure to compare amps and cfm, then decide if your charging system is up to the extra task.
For a while I used a Flex-a-lite 17" fan with the flat front and even bent narrow fan blades. It fit the tight location but moved very little air. After moving the radiator forward, I was able to switch to 17" curved, much bigger, blade fan which moves a ton more air. Even with the radiator 10" from the grill, I can still feel the air moving when at a fast idle.
I do agree with 46gmc, go as big as possible with the maximum cfm offered if you choose to go this way.
Joe
