This is GM Performance Parts best pushrod for small-block and V6/90 degree Chevrolet racing engines.This 5/16" diameter pushrod is manufactured from tough 4130steel tubing with a .080" wall thickness. Test have shown that this new premium quality pushrod is 35% stiffer that pushrod P/N 366277. It will withstand a bending force of more than 4700 pounds.This pushrod is .100" longer than stock. Its one-piece design eliminates tip aligment problems. Premium 4130 pushrods are case hardend, and can be used with guideplates.