I may be wrong, but I remember o rings where the bar plugs into the head. No big deal as I made some out of rubber tubing with a razor blade. The spray bar is held on the head with a bolt thru tab made onto the bar. If the tab should break, which they do from time to time, the oil pressure will push the bar away from the head and make one hell of an oil leak while filling up the valve cover with oil. It can get so bad that there will no longer be enough oil in the pan to feed the bearings. After that happened to me, I always safety wired the bar to the head.