Diamond Power Intake & Exhaust Valves works with Oldsmobile Achieva 2.4L DOHC 2 Year Warranty (This product must be installed by a certified professional mechanic) Same day shipping when purchased before 3pm EST Our products are tested and meet or exceed OEM performance requirements Fits 96-98 Oldsmobile Achieva 146 2.4L DOHC L4 LD9 VIN "T" Engine Valves are made with excellent quality materials (Nickel, Chrome and Tungsten)