Thanks dave500, I found some info that it could be done, but I really wanted to hear it from the SOHC geniuses/ gurus/ experts/ hotshot/ Maestro/ well you get it!
I had a 1974 CB750 in the mid 70's and I took the head off and I also don't remember removing the engine.
I painted the head Red and cylinder black to resemble a Dunstall 750 Norton I saw in a magazine, I wonder what happened to that bike.
thanks again, Mark