I've verified with the manufacturer catalog that this Vacuum Power Brake Booster - Part # 54-71085 is an exact fit for your 1998 Chevrolet K1500 Pickup. That spacer maybe an upgraded version of the original [Reference Number]: The A-Premium Power Brake Booster's reference number: 54-71085, 5471085, 18029873, 18029874, 18047682 [Superior Quality]: Power Brake Booster are coated with anti-rust coating, which can effectively prolong the lifespan. [Vehicle Fitment]: Compatible with GMC Yukon/C2500/K2500 1997-2000, C1500/C2500 Suburban 1997-1999, K1500/K2500 Suburban 1997-1999, C1500/K1500 1997-1999; Compatible with Chevrolet Tahoe 1997-2000, Sonora 2000-2001, C2500/K2500 1997-2000, C1500/C2500 Suburban 1997-1999, K1500/K2500 Suburban 1997-1999, C1500/K1500 1997-1999; Compatible with Cadillac Escalade 1999-2000 --- It comes without Master Cylinder A-Premium Vacuum Power Brake Booster Compatible with Select Chevrolet, GMC & Cadillac Models - Silverado 1500 2014-2018, Tahoe 2015-2020, Suburban, Sierra 1500, Yukon, Yukon XL, Escalade, Escalade ESV, Power Brake Systems - Canada Upgrade Your Chevy Truck with the Best 88-98 Grill – Get the Perfect... Premium craftsmanship and materials ensure superior quality and durability, and excellent performance enhances the whole braking system. A-premium Vacuum Power Brake Boosters are an ideal choice to replace your broken Vacuum Power Brake Boosters. Vacuum 54-74826 For Cadillac Escalade, Chevy Tahoe Silverado Gmc Yukon 2003 We offer a wide variety of automotive accessory categories, ensuring that you can hit the road with peace of mind.