I'm not sure on how to decipher cam lingo and I realize that there are a lot of variables involved however.......Kastner Competiiton manual says They are refering to a "D" spec cam here)."You will find that with an optional camshaft fitted,more fuel will need to be be available. So install a pair of RH needles in the S.U. carburetors." I have an M518 camshaft: duration 227degrees@.050"......280"camlift....420"valvelift on 109 degree lobe c/l. Anyone know if replacing the standard SM needles with the RH needles in the SU's would make sense with this particular fast road cam? Other mods were header, TR4A intake manifold, Petronix ignition.