While the ZR2 Bison does not add anything under the hood (you still get 6.2L V8 and 420hp) as the Silverado ZR2, the outside enhancements are notable. Chevy turned to AEV to add 18" gloss black wheels, stamped skid plates, and floor liners in the $7,800 Bison package. You do also get the Multi-Flex tailgate.