Thanks for the replies... h16Sailor, glad to hear from another sailor down here in L.A.
The Perkins 4-108 is not an overhead cam (I am 99% sure anyway), and I think it is an original 1979 block from the original purchase of this boat. I am going by the serial number for the engine.
winterbuoy, thanks for the book info, we do have the "Marine Diesel Engines" book and I would recommend it to anyone as well. Didn't know Foleys or Nigel or the other two books so thanks very much, I will check them out.