6 Pushrods come in many flavors, but for the most part you'll find the typical steel tube in 5/16-inch diameter with welded pivot ball ends, as these examples are seen here. They work fine for a stock engine, but like their sled rocker arm counterparts, are not the most accurate. They can flex enough with aftermarket springs/high lift cams to reduce the amount of true lift the valve sees. Plus they are not hardened to work with pushrod guideplates (the pushrod actually rubs/touches these plates to keep them in line with the valve it actuates). Finally, we've actually seen the pivot balls fail at the weld with aggressive cam profiles.