99 chevy silverado 2500 5.7 reg cab 3/4 ton long bed 4x4

silver,
check the hp rating for this engine
I had an old style 3/4 chevy truck 2000 model with the 350 engine,
it only has about 250 hp with 330 lbs of torque.

so on a long hill it would start to run out of power, I always pulled in 3rd gear, not overdrive and it was ok, but never pulled in the smokies or such.

I traded and bought a dodge diesel, 2005 model, 310 hp, but with 625 lbs of torque, wow, no problems pulling.

the big over the road truck do not have all that much hp, but the engines have lots of torque.