"Edelbrock E-Series Cylinder Head Bolt Kit #85312 is designed for use with Edelbrock Performer Cylinder Heads #60129/#60139 and Performer RPM Cylinder Heads #60109/#60119 used on pre-1970 AMC engines with 7/16-inch diameter head bolts. This kit contains all of the necessary parts to replace the factory head bolts. E-Series bolts have a yield tensile strength of 190,000 PSI for strong and reliable loading. Bolt threads are rolled after heat-treating for superior form and strength, while a small hex head provides extra space for socket clearance in tight situations. E-Series Cylinder Head Bolts have a durable black oxide finish with sealer and come with the distinctive Edelbrock “E” stamped into the head."