So, I have posted a few posts trying to figure out my extremely loud fan. The reason it interested me so much is because in my yard, we have my 1996 z71, two 98 k1500 4x4's and a 97 z71. My fan on the 1996 is a five fin fan whereas the others are comprised of 11 fin fan blades i believe. When i hammer the gas, the fan makes an aggressive roar, theirs has none. Inside their trucks it is completely silent except for their exhaust. We all have basically the same semi-illegal set up for exhausts, true duals, two cats and straight pipes no mufflers. They say that mine is the loudest from behind, but my unrelentless motor/fan noise inside of my truck while driving deprives me of the privelages of hearing hippies die when i give my pipes a yelp. In my research, i have found that one of the improvements to the 97 model was making the fan less noisey (For '97, Chevy has not changed their line significantly, but has added a few noteworthy items. For one, a passenger-side air bag with key-operated deactivation is offered with the latter likely becoming standard as a result of recent fatal accidents to children and small-statured adults. Also new is an improved HVAC system, tighter turning radius for 4WD models, a more responsive electronically controlled variable assist power steering, improved automatic and manual transmissions," a quieter and more efficient cooling fan", three new exterior colors and a natural gas-powered 5.7-liter V-8 engine. ) -------http://www.theautochannel.com/vehicles/new/reviews/1997/nhromiak09019702.html I would love to be able to enjoy the sound of my exhaust without the sound of the loud roaring/ 1st 5700 series vortec. Besides installing a 1997 motor into my 1996 body, is there anything else that I can do? I thought of putting in a fan from a 97, 11 plastic fins instead of my 5 steel fins, but I am not sure of the internal components that are combined to create a more efficient fan. What do you guys think? P.S. my truck is completely stock, brand new tensioner, idler pulley and belt, 109,000 miles no motor work done at all, absolutely stock with regular maintenance... Have at it!