Hi All - have a used (new to me) set of above with snails; there are two fittings on front of log and two larger fittings on snail; one of these is blocked with plug.  Question is what is hookup for front two small fittings and one snail fitting.  Have closed system so is there a way to preheat the water thru logs and send into the water pump? ideally this would be working prior to thermo opening.  also on SBC water pump their is plug on pump - what is this for?...also have one fitting on front of intake manifold available.........thxs kenai