I got mine from Clearwater. They were nice to deal with on the phone. It's cast with no jet valves and comes complete with everything except the valve cover. http://www.cylinder-heads.com/index.cfm
Marnal are supposed to be way better, but I'm happy with mine. It's got 4k+ miles on it and no problems. I took the money saved compared to buying a Marnal and put ARP studs and a Weber carb while I had it apart.