My brother is using the 440 source housing, pump and thermostat neck. The pumps impeller lightly scraped the inside of the housing without using 2 gaskets for clearance. Also the bolt spacing was different between the thermostat neck and water pump housing...the bolt holes in the thermostat housing had to be widened quite a lot to be able to bolt it to the housing. The castings all looked nice but the machining was a bit off.