Ported LD4B :(

i'd suggest you just gasket match it and not "full on port" them. get some color on the head surface, use a gasket as a template and scribe a line. i don't know what you skill level is or how much experience you have with a die grinder or porting, but if you're relatively new to this type of thing you can start out with some sanding rolls like these

you're not removing a tremendous amount of material, and these are very forgiving if you get a little Shakes McGee with the tool.