Thanks guys, I figured it out, the return spring for the throttle is attached to a bolt that is stuck in that hole on mine. I got it out, and spent the better part of the last four hours trying to get the thing cleaned out and flowing freely. No luck. Dug lots of gunk out of there, then attacked it with degreaser, got more stuff out of there, flushed it with brake cleaner, more junk came out, went at it with a pump sprayer of muriatic acid, its running clean out of there. But nothing will drain down from the upper part of the block either. As the head and water pump are removed, I can tell there is no water being forced up thru the block opening either. Any suggestions?
