[HUMMERcustoms.com/TAZ]

I agree with GLBLWRMR if I spelled it right. I do use Royal Purple in all areas of H2 though because I'm running such high boost, HP and Torque. I do as He says and do not extend changing times. I follow the old school book.
I also have several trucks well my rule is put 250,000 miles before I get another work truck and have run Penzoil on the last 2 which one was a diesel. Niether of them would use enough oil in 3000 miles that you could really notice. I did use K&N air filter systems. The present 99 Silverado which is a everyday truck not work truck has 150,000 miles on it and oil changes extended to 5,000 miles. Penzoil used along with K&N, Hypertech, dual exhaust, flowmasters and all the peformance stuff i can run on it. Will be tuning it soon with HPTUNERS software since i got it in from my sponsor of H2 to use. The Silverado is for peformance fun and love to see the rice rockets face when i run off from them. I use Penzoil and change plugs sooner than book says. It just rubs Me wrong to run spark plugs
100,000 miles just like I cannot run K&N filters 50,000 miles before cleaning. I use new tech. with old rules and seems to work well.
I most likely should use Royal Purple on the 99 Silverado but, I used Pen on it from new and makes Me feel wierd to think about changing what the old girl has been used to. I use regular oil in everything I just SO in H2 because of all the real high stress that is put on it occasionally. Hummer sends it out of factory with GM SO in it in certain areas I just figured it would not hurt to go 100% SO in this rigs circumstances with Us pushing it with more and more boost and water/methanol inj. all that kind of stuff.

I also saw on Speed Channel it was HP TV show where they took a camaro and ran it on a dyno with regular oil then switched to SO oil and the rig gained 8 HP just by changing to Royal Purple, for what it is worth.

TAZ