There is MUCH more to cams than lift an duration. Changing your cam profiles moves your power band around more than adds/subtracts power. When modifying your cams think more about where on the powerband you want to make the power. Keep in mind that it's easier to make power at higher RPMs.

Here is some info on what camshafts do for your motor and what effect changing them will have on your overall performance. It's for the 4AG but the rules apply to all of us.

http://www.club4ag.com/faq_and_tech_pages/4A-GE%20camshaft_story.htm