You cannot use the 83-84 XR or XL500 cylinder heads. You have to use the earlier 79-82 ones. I know that it works because I had one sitting on a 350x cylinder at one time. I'd go take pictures of it right now but I got rid of all my XR500 stuff, Lomax has it. He could probably snap some pictures if need be.
One can only beat their head up against the wall so often before they get blood in their eyes.
Note to members: Stupidity is a BANABLE offense, mods can decide if YOU are being stupid and WILL ban you!