I found out that if you use hot water heat with an Offenhauser 2x1 or 3x1 on 216, 235 or the 261 Chevy, that you need to pull out the two small metal plugs from the bottom of the Offenhauser intake manifold and weld an aluminum slug it their place. The Offy pressed in metal plugs are not water tight and they will end up dripping water.
I don't know if the later 250/292 intakes have these plugs or not, but if they do they will also leak.
The aluminum slugs that I used were .125" thick by .850" diameter and fit real well after I had drilled a 3/8" diameter hole in the Offenhauser stock metal plugs and pried them out with a screwdriver.
If anyboby needs a couple of aluminum slugs to weld in, contact me as I have a few extras at no charge.
