Inlet valve guide, P2 series N2 to 50 in O2

The original Rolls-Royce practice was to manufacture Phantom 2 inlet and exhaust valves with the same stem diameter, and build the different valve stem clearances in to the finished diameter of the valve guides. This requires different size reamers to finish the valve guides to final size, and is contrary to most modern practice. For Phantom 2 our valves are made with different diameter stems for inlet and exhaust, and the valve guides are all reamed to the same diameter.