I have used the search function but somewhere on the site I stumbled upon a link for a video showing the inside of a 502 thermostat housing. I'm adding freshwater cooling and I'm trying to figure out what thermostat housing fits with me MPI intake . I called a big vendor and they were not very helpful other than offering me a complete kit. I thinkbthat I can modify the factory housing if push comes to shove . Any help would be greatly appreciated.

Edit in: thought you meant raw water. My bad.

Closed is the same as freshwater cooling i think. Anyway I have a thermostat housing for raw water cooling. I need to get coolant in and out of the motor. My plan is to use the factory manifold and weld a 1.25" bung in place of the 1" port on the top right. Then fill the front of the casting with epoxy and drill from the 2" port to the 1.25 port on the front right. Ill use a hose mount fill just after it . I dont have room for the heat exchanger on the front of the motor so ill mount it on the right side of the engine compartment.

The thermostat housing for monitor pro is pretty simple and the kit comes with it and the tstat. It’s really an easy system