I know over the last while, there has been much discussed on the subject of 351C thermostats, which are right and which are wrong. The original (RobertShaw) type are the preferred ones, however, what I'm using is the Stant 13469 which is a 195 degree. It does have a sort of 'hat' and is sold as the correct one for the Cleveland 351 C. I also have a couple I bought from NPD and branded as Parts Master. Guess what folks, they're identical, same marking, same tooling draw lines. The number on the NPD part is 22392 and notes it replaces MotoRad 223-192 and labeled 351C, 70-73. ( I have Stant and NPD 180 degree ones as well, just not using them)
Anyway the Stant 195 stat I am currently using without any overheating issues whatsoever even in the 95 Degree temps we have had lately here. My new gauge has never gone above the 190 mark. So, does this really seal off the center hole in the plate? I guess it must and if it does, why pay 25 bucks or more for the fancy one if the 3 dollar one does the job. If it's overheating and you know there is a Cleveland type stat in there, my guess is something else is wrong and it's NOT the stat (unless it's faulty of course). I have no doubt someone will challenge my view-point.
Geoff.