how important is the shroud around the flex fan?..does it make a dramatic difference in helping to pull air thru the rad? [thanks]

 

You betcha! Anything you can do to focus the dsraw though the radiator and not the surrounding area, will improve the efficiancy of the cooling system.

On another note, lose the flex fan and go with a factory type, I've had a few come apart, and I'm sure I'm ot the only one around here who has.