You may have noticed from prior articles there were two different intake manifolds for SU carburetors on the Twin Cam engines. The early SU manifold is shown on the left and the later on the right. Although an exact changeover point was never documented, as a guide YD3 816 (G430) has the early manifold with the extra lugs and YM3 1035 has has the later manifold. It is suspected that the early manifold was designed for either another type of SU, Solex carbs or even Lucas fuel injection.

Also notice the welded lump on front end of the intake manifold for mounting of the generator. This weld is original factory issue for the Twin Cam.