Check the axle ID tag on the back of the rearend, you'll find the ratio there and whether it's got traction loc too. I'll bet it's got 3.55's, if so it'll have 3 55 stamped there, if it's got trac-loc, it'll have 3L55. And for a truck, you want to move towards more torque output, not HP, especially with a 302 turning larger diameter tires.