Fits HEMI CNG Engine.; Mega Cab; Med. Duty 2WD or HEMI CNG Engine.; Regular Cab; 8 Foot Bed; Med. Duty 2WD or HEMI CNG Engine.; Crew Cab; 6'4" Box; Med. Duty 2WD or HEMI CNG Engine.; Crew Cab; 8' Box; Med. Duty 2WD