[THEFERMANATOR]

They all have a recess in the intake, GM cast them that way for street use. You don't want to run them that way in marine though. When your running along at a cruise, there is to much water pressure on the backside of the T-stat and it will cause the T-stat to not always open. The marine engines are designed to constantly circulate through the block in a raw water cooled configuration. This is to keep the cold incoming water from cracking the the block. When you install the T-stat direrctly into the intake, everytime it opens the engine will suck all of that extra cold raw water straight in without it being able to mix with the already heated water. I shipped out that housing to you, run it and I'll guarantee you it will work. Worked great on the last engine except at idle. The ALPHA's pump just didn't have enough to flow a BRAVO housing at idle.