GMPartsGiant.com offers the wholesale prices for genuine 1999 GMC Suburban C2500 parts. Parts like Spark Plug Wiring are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 8 Cyl 5.7L, 8 Cyl 6.5L Diesel, 8 Cyl 7.4L. Model Code: 3/4 TON.