I want to say they have an o-ring on them and go in dry? If you do use one of the block type do yourself a favor and pick a spot that is easy to access, and not buried behind a motor mount or the headers. Also the plugs may not fit in just any hole depending on where the cylinder is behind the freeze plug opening. I tried putting one in a siamese bore 400 sbc years ago and could not get it to fit so I had to use the lower radiator hose type instead.