I was just at the Towe Auto Museum in Sacramento and I belive that the old Chryslers (I could be wrong about the make, but it wasn't any GM brand) had "L" heads, which seemed to refer to the cylinder valve relationship. I believe that this was not restricted to only 6 cylinder engines, but was also used in reference to straight 8's. Now I gotta' do some internet surfing to find out for sure, or I won't be able to sleep tonight.
