Zipper’s Step-Lock Valve Guides

We’ve never been big fans of the shoulderless valve guides used by the factory in EV & TC heads, so we designed our own. Our ductile cast iron Step-Lock guides have a shoulder that helps set the guide to the correct depth, and, in the event that the engine is severely overheated causing the guide to come loose in the head, allows the lower valve spring collar to capture it, keeping it in place. The top side of the guide is machined to accept larger .531″ ID seals while the port side is tapered to enhance flow around the guide. Requires use of stepped lower valve spring collars (our Crane spring kit collars work fine without modification). We offer lower collars to fit the spring kits we sell for use with these guides. Sold each.