If you are looking for even more out of your vw cylinder heads without the need for a machine shop then upgrading to these big valve heads with included performance valve job is the answer. All the benefits of a performance head wrapped into an off the shelf package. All heads are complete and include 40mm intake and 35.5 exhaust valves. Single or dual valve springs, chromoly retainers, hardened keepers and 12mm 3/4" reach spark plug holes. All heads have had a performance valve job to add in performance. Choose your Bore size and spring options. Heads are sold EACH.