Fitment and Product Information. Head Stud Kit For KA24E 2.4L 4-Cylinder. When racing professionals in NHRA, IHRA, NASCAR and Formula 1 competition need bullet-proof fasteners for their high-performance machines, they turn to one company the “ARP”. Since 1968, Automotive Racing Products has been engineering and perfecting bolts, studs, nuts and other fasteners for engines, cylinder heads, headers, wheels, transmissions and more. ARP uses only top-quality materials, far above the usual aerospace quality others settle for a highly exacting manufacturing process to create fasteners with the strength and durability to last race after race. WARNING : This product can expose you to chemicals including Styrene, which is known to the State of California to cause cancer.