the only two manufacturers of electric fans that I recommend are Spal and Tri-Pac. they actually flow their advertized air.
Agreed on the Spal fan, I have one on mine. I don't recall the specs or model number, though.
Another tip you might try in additon to the shroud; swap the fan to a 5 blade fan from a School Bus. I installed one from a '58 School Bus after the original got bent (that's a hole 'nuther story), I haven't had to use the electric fan since.
