5.7L vs 4.8L

I was just wondering this. The other day me and a co-worker raced. I have a 97 Sierra with a 5.7L vortec with True dual flowmaster and K&N intake and he has a 05 Silverado with a 4.8L vortec with straight pipes, both are rcsb also both 2wd, both automatic. We went from about a 15mph role, he was at my back bumper and punched it, I didn't punch it until he was about at my door. He pulled about a front bumper infront of me and we stayed there until about 75 then I started inching away from him. My truck is rated at 255hp and his truck is rated at 285hp shouldn't he have been able to out horsepower me and take off? Do I have more torque then the 4.8L and that is why I kept up and starting taking off? Or is my truck just underrated and closer to his hp?

your engine may have more torque.it could be that simple.but other factors such as gearing also have an effect on the truck.when the 4.8s like mine fall below their powerband they dont have much pickup.between 60 and 75 if the truck is in 3rd gear it doesnt move as well as if it drops to 2nd and revs to 4500 or 5000.condition of the trucks drivetrain also has an effect.as close a race as it apparently is, those little factors start having more of an effect on the outcome

the 350 has 325 ft lbs of torque the 4.8 is just over 300. So you would have the advantage there.