For one, this truck isn't an SS. They only made the SS in extended cab. The SS had specific front ends, wheels, and lower side panels. The work done to this truck to make it look like a real SS is extensive and it turned out great.
There was also a Vortec Max model that would give you the same engine in the 1500 without the looks of the SS.
https://en.wikipedia.org/wiki/Chevro...t_Silverado_SS