Edelbrock E-Series Cylinder Head Bolt Kit #85562 is compatible with Pontiac engines with Edelbrock Performer and Performer RPM Cylinder Heads #6056-6058. Note that this head bolt kit is required to install these Edelbrock Pontiac heads. The 6056-6058 cylinder heads require a head bolt kit that is similar to that needed for a Ram-Air IV head, which is different from a standard D-port head. Several of the bolt boss heights have been increased to enhance the potential of the heads. 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.