I need to replace my thermostat housing on my 66 Mustang 289. I have noticed there are two types. One with a gasket or one with an o-ring. Which one would be the best?
either one will work fine. ive used both. i tend to like the gasket/sealer type better. a suggestion i have is not to get a cheap housing(crome plated type) from your local parts house. ive had troulbe with them not sealing and warping easily. use a good o'l cast iron one.
the chrome plating tends to allow more leakage than a regular iron or aluminum housing does. i like the o ring type in theory, but in actual practice i prefer the gasket type, as it just flat works better.