Your engine probably doesn't make any more power after 5,000 rpm, no matter how high it revs, the stock efi doens't breath terribly well past that point. Tire size, transmission and gear ratio have absolutely no relevance to the actual power output of your engine. The only reason I could see for you to rev over that point would be if you knew you were going to bog a little and wouldn't be able to rev any higher after that point. If you wanna make good, usable power higher in the rpm range on your efi setup it'd cost you a fair amount, but lc engineering has a decent looking power up kit for your truck. That's really where the carb trucks have the advantage, with a hybrid setup like many of us are running it's not real hard to get usable power well past the 6,000 rpm mark. Sorry to rabbit trail, and welcome to the site