Ford 4.6 Triton

I tow with a 2004 F150 ,2 valve 4.6, 3.55 gears and so far its the road that limits my speed ,yes it does drop to 2nd gear and turns hard up hills but it does maintain about 55 mph, some of you need to drive a HDT grossing 60k with a 275 hp 800 torque engine, and then you will see what underpowered means

4.6 40 pound per hp , 38 pound per lbft torque

HDT 218 pounds per hp 75 pounds per lbft torque