Location of engine number on a 1955 Jeep

My younger brother has a 1955 Jeep CJ5 with a 134 cubic inch F-head engine (original engine). He says there is supposed to be an engine number stamped on the engine but he doesn’t know where to find this number. Can anyone tell me the location of the stamped engine number for this make and model?

I don’t know, but there are people on jeepforum.com who do.