I recall there is an issue, at least with some heads, that if you use the wrong thermostat gasket you get coolant into the intake...I know this happened to me once years ago. I was putting my motor together today and found the thermostat gasket that was on the thermostat housing is different than the new gasket (from an FI gasket set). The gasket on the right is the old one and the one on the left is the one that came with the gasket set. The old gasket matches the opening in the thermostat housing but the new gasket matches the head. The thermostat housing came from the motor that was spitting out thrust bearings and I want to use it on this new motor as the thermostat is new and I know this worked great. I note the fourth hole in the thermostat is a blind hole. Two more pics below. Middle pic shows the head and the lower pic shows the thermostat with the new gasket. So, the question is, am I safe using this thermostat and new gasket on the FI head? Anyone know what X motor this thermostat housing is from? Was the water in the intake just for the 79/80 carbed heads and this is all a moot point if I don't have that head?