My Performer 318/360 intake although crusty and old like me, does not have cooling passages in either sets of t stat housing bolt holes.
1st two photos show what toolmanmike is referring to with the machined pocked (stock t stat housing).
Not sure if the billet one has this provision.
Photos 3 & 4 show bottom of all t stat bolt holes cast closed off. I can not run my pick down through any of the 4 bolt holes.
I am still suspicious of the O ring system.
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