Interesting because I have a twin L myself, same spec and that part is not the same. Wondering how the oil is drained? You are in luck,, I think? Pictured are the same elbow from a very early 10/2 I own and also a 16/2 Listeroid. I do believe that either would work perfectly in place of your original. I didn't check this out to the inth degree because I didn't want to remove them to check. The CS engines are descendents of the model L and share a sone parts. first pic in my TL notice oil drain plugs, next is my 10/2, last is the Listeroid twin. Any of the CS/Listeroid parts would be easier to find than twin L parts.