Assembled with manganese bronze valve guides, powder metal interlocking valve seats, stainless steel one-piece valves with hardened tips, 1.25" diameter valve springs, 3/8" screw-in studs and guide plates. Additional qualities include hardened spring cups for long-term wear protection and Heli-coil threaded inserts in the rocker stud bosses for increased strength; these are the details that most low-cost competitors leave out of their heads.

Technical Notes: Use with hydraulic camshafts .550" max lift. Recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat. Requires hardened pushrods. 

• Ideal for operating in the idle to 5500 rpm range; Use with hydraulic flat tappet camshafts, .550" maximum lift - not compatible with hydraulic roller camshafts; 289-302 with 7/16" head bolts require #9680 head bolt kit; 2.02" heads require additional piston to valve clearance; Recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat.; Requires hardened pushrods. 289-302 c.i.d. with 7/16" head bolts requires #9680 head bolt bushing kit.

Not legal for sale or use on pollution controlled motor vehicles.

Sold in pairs and Made in the USA.