Edelbrock E-Series Cylinder Head Bolt Kit #85502 is a high-quality replacement set of bolts with washers for small-block Chevy engines equipped with Edelbrock Performer RPM aluminum heads. This bolt kit is required when installing Edelbrock aluminum heads on an engine previously equipped with cast iron heads. Bolts used with iron heads do not require the use of washers. Washers are required with aluminum heads and the bolts in this E-Series kit are longer to compensate for the thickness of the hardened washer. E-Series bolts have a yield tensile strength of 190,000 PSI for strong and reliable loading with generous filleting throughout to eliminate stress risers. 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.