Thanks for the replies people.  My truck is a flare side extra cab.  It's my daily driver so I probably wouldn't go with the underdrive pullies.  A Lightning blower sounds like a good idea though...

   You think there'd be any Eatons for sale on the site links you guys posted?  I have my '90 Mustang w/ a rebuilt 306 & 150 shot if I want to go real fast.  I was just looking to beat the Silverados that some of my buddies drive.  They seem to pull me on the top end.  If I did change gears I'd probably go 4.10s...but that would kill my gas mileage since I have stock wheels and tires on there.  The 3.55 gears are actually ok.  Hmmm...what to do?  Guess I'll just go with some exhaust for now.  Since you don't recomend a Gibson exhaust 95GTS...which exhaust do you recommend?