12 degrees BTDC sounds about right, and is probably not the cause of an overheating problem. Could be the cooling system has weak components such as a partially clogged radiator or worn water pump. Could be the cooling system is too small for the application, or the fan shroud is inadequate. Also could be an unusually lean condition in the carburetor.
The standard horsepower of the Chevrolet 6.0 liter engine that comes in the Silverado is 360 horsepower. This is a V-8 engine.
Horsepower ranges from 300hp to 400hp.
The horsepower of a 1991 Chevrolet 454 cubic inch engine ranges between 240 horsepower and 350 horsepower the engine torque ranges between 700 pounds and 850 pounds.
Chevrolet didn't make a I52 engine.
Horsepower ranges from 185HP-315HP.
A 6.0 liter 2003 Chevrolet engine has a horsepower of 300. The engines are used on heavy-duty, full-sized trucks and vans.
The 2014 Chevrolet Camaro's engine produces 323 hp @ 6800 rpm.
The 2007 Chevrolet Suburban's engine produces 320 hp @ 5200 rpm.
The 2009 Chevrolet Impala's engine produces 211 hp @ 5800 rpm.
The 2007 Chevrolet Malibu's engine produces 144 hp @ 5600 rpm.
The 2001 Chevrolet Tahoe's engine produces 275 hp @ 5200 rpm.
The 2006 Chevrolet Colorado's engine produces 175 hp @ 5600 rpm.