B3-23A 30 Plate Heat Exchanger, its an earlier version without the mounting studs:http://www.dudadiesel.com/choose_item.php?id=HX2330
Taken from my old system that was shelved about 2 years ago, can certainly use a good cleaning. $85 takes it.
What size fittings are these? 1/2" or 3/4"?