Jim, a long time since I worked on a flat head engine, but don't remember having to pull the engine for a valve job. Perhaps, but I think not. Don't want to burst your bubble, but valves generally get looser, not tighter. A loosely adjusted valve would prevent it from opening all the way. For adjustment to be the culprit, it would have to be tight enough to prevent it closing. The head will, of course , need to be removed to do a valve job. A close inspection at this time should reveal if the engine has indeed been rebuilt. Since your pocket book is like so many of ours, perhaps just a valve grind, if needed. If the rings are badly worn, this MAY cause a little more oil to be burned, but just live with it until you can do more. Don't despair.!! Ben