I am looking at these Apache cylinder heads, left and right, and they are side specific.
What I have figured out (if I am correct) is;
-Exhaust bolt pattern is different, there is boss material there to drill and tap to make them both the same.
-the right head exhaust flange has an added hole as well as a threaded hole. This I have no idea as I don't have an engine to look at. Does anybody know what they are for? Lower head left side.


-Next to the intake ports are cut-outs. I take it that one is for oil filling, what is the other for?


To make these heads work for either side the exhaust bosses would need to be drilled and tapped.

Also each head would need to be drilled for oil return at the back of the head. It seems like there is enough material there to do this.


Any thoughts, comments or answers would be appreciated.