Need cooling help please

[Lee Patterson]

I would machine the housing if you have that much interference. Basically you are trying to seal two "perfectly flat" surfaces but for the fact there is a bulge being created by the thermostat sticking up too far. I just looked at the Motored (Stant) thermostat for the 302 and it measure 1.75mm at the flange thickness and is 54.1mm diameter. What a PITA for sure!

 

[David mono]

I measured the depth for the thermostat on one of my housings, I had .98mm and the thermostat was flush with the sealing surface.
I'd RTV the thermostat to the housing and let set up before assembly so thermostat does not drop between housing and intake.