Cadillac 331ohv v8 engine number

Hi I am trying to find my engine number on my J2 as I know my car has had a number of engines in it’s time. It has a very badly fitting dipstick and sheaf which is leaking oil onto the exhaust which looks like I am doing the 007 smoke screen which I would love to replace . It also leaks oil from the the oil filler cap which has a drilled hole in the top. The engine has been modified to give a modern oil filter bypass which also has a breather so I was wondering if I could seal the hole? I have searched all the usual places to find the number and the only numbers I can see are obstructed by the bottom of the oil filler pipe and heat tray below the carburettors.see picture any help would be most appreciated. Max