For 1988-1995 SBC Chevy Black Coated Truck Headers GMC 1500-2500-3500 Heavy Duty fits 1988-1995 Chevy/GMC 1500, 2500, and 3500 pickup 2WD/4WD (except 88-91 1 ton crew cab dually) fits 1992-1995 Chevy Tahoe and GMC Yukon 2WD/4WD fits 1992-1995 Chevy/GMC Suburban 2WD/4WD fits SB 265-283-305-307-327-350-383-400 Chevy engines 1 5/8" diameter tube, large 3" collector,built in hole for the oxygen sensor.3/8" thick flanges ,extremely heavy duty.