http://www.holley.com/types/Super%20...WD%20Truck.asp
2841-1HKR
68–87 Chevy/GMC 1/2, 3/4 & 1–Ton Truck, 68–91 Blazer/Yukon/Jimmy/Suburban/1–Ton Crew Cab: 396–502
Full Length Header Tube Size 2" x 35", Collector Size 3.5", Collector Length 10", Port Shape: Same As Port, Metallic Ceramic Coating
2841HKR
68–87 Chevy/GMC 1/2, 3/4 & 1–Ton Truck, 68–91 Blazer/Yukon/Jimmy/Suburban/1–Ton Crew Cab: 396–502
Full Length Header Tube Size 2" x 35", Collector Size 3.5", Collector Length 10", Port Shape: Same As Port, Black High temp paint