I'd bet it's your intake/exhaust manifold gasket. The high idle may be from it sucking air, and that could be the squeal you hear. Mine had some of the bolts broken when I got it, and some of the gasket was gone. It was so bad that I could press against the side of the throttle body with my hand and the squeal would lessen and the idle would settle down. Or spray some starting fluid around it and see if the idle increases.