I used to have a chrome thermostat housing on my 454 in my 70 Chevelle, I was tuning the engine and had managed to get the engine kinda hot,I had left the fan shroud off and decieded now would be a good time to put it back on as I pushed the shroud down it caught on the upper hose and with way to little effort the
upper hose slipped right off of the housing and proceeded to steam my arm like a crab,that was the last chrome housing I'll ever own, I guess it could also happen with a cast housing but not that easily.
As far as gaskets for the housing I always make my own out of thin cardboard,the kind like gaskets come in, it's very simple just hold the cardboard over the housing and either trace the outside with a sharpie or just cut it with scissors, pressing down on the card board to hold it against the housing you can cut the inside out with a knife, and for the bolt holes make an impression with the bolts and then cut them out also,It works great I haven't had one leak yet, and all the money saved on buying gasket's can be donated to the board
MPB