Mr. Gasket Harmonic Balancer Bolt for Ford V8 except 351C. Fits 221,260,289,302,351W small block Windsor engines, 332,352,360,390,406,410,427,428 FEs, and 429,460 385 series big blocks. 5/8-18 x 2 inch long heat treated black oxide coated Grade 8 alloy steel with a thick parallel ground washer to provide accurate, uniform torque.