Definite;y find somebody that can do ultrasound cleaning. WAY better than dip and squirt. Also make sure they back flush them first to get any impeller pieces out of the intake manifold, which is permanently installed and hard to see into. Be careful with the torque on the bolts when retightening the halves together because they can bend the flanges easily. Sorry, don't know costs, maybe $50 each for ultrasound?
Doug