The Edelbrock Hardened Steel Pushrod is designed for use in engines with or without hardened steel guide plates. These pushrods are manufactured from case hardened tubing with a surface hardening. It is a 5/16 (+0. 100 longer than stock) pushrod. The overall inlet and outlet diameter is 7. 9 long. It has ball ends, which are welded to maximum durability. The guide plate slots must be of the correct width for 5/16" pushrods. All parts should be lubed thoroughly upon installation. The preferred oil is moly lube or motor oil. It is sold as a set of 16.