I noticed some guys are running the Hayden 2991 severe duty and some are running the 2744 heavy duty, anyone care to share their opinion? I read one thread that a member said the severe duty was overkill and strained the motor and affected mpg's...

 

if it gets up to 100 degrees where you live, then you know the answer. You can never have too much fan to TRY and keep the Rover V8 cool. I got a 2991 model and I can't see what all the fuss is about. I can hear it pulling good when I take off from a complete stop until after 3rd gear but its nothing I haven't witnessed on any other full-size pickup.