Yes same engine.
The 2003 Chevrolet Silverado-1500 has a V6 engine.
The 2003 Chevrolet Silverado-2500HD has a V8 engine.
The 2003 Chevrolet Silverado-1500 has a 4.3 L base engine size.
The 2003 Chevrolet Silverado-2500HD has a 6.0 L base engine size.
The 2003 Chevrolet Silverado-2500HD's engine produces 300 hp @ 4400 rpm.
YES they are the same engines.
The 2003 Chevrolet Silverado-1500's engine produces 200 hp @ 4600 rpm.
The 2003 Chevrolet Silverado-2500HD's engine produces 360 ft-lbs. @ 4000 rpm.
Under the engine
The 2003 Chevrolet Silverado-1500's engine produces 260 ft-lbs. @ 2800 rpm.
The Silverado comes with a lot of different GVW capacities and engines. I think if the Silverado was a half-ton regular cab short bed with the biggest engine package, it would be a very close race for the Camaro.