Slant six spark plugs and numbers

That helps. It is probably a '75 engine, or at least head. Now I have something else to look at. I'll see what plugs a '75 used and see if that matches.
Thanks.
My brother put a Cadillac engine in his Ford car hauler truck. So anything is possible with the right tools and skills.
Edit- Just looked up the '75 parts. Sure enough that's what I see in the engine. Now I know what I'm dealing with. Do you know where the numbers are on a '75 225 engine? I haven't found those either. That would probably have answered my question right from the start if I had found them.
Thanks again. Solved a lot of head scratching.