Head is a 30.5mm by 27.5mm valve set up. Porting was done by JD of SI valves. Welding was done by MDB. I had this head re-surfaced to true it up best it could be done, also had it unshrouded, re-lapped the valves also had the guilds knurled. Champion roller shaft rockers, and this head has duel springs with the billet keeper and retainer set up. Head is sold as for $175.00 plus shipping. Local guys I will work with on pick up/delivery.