Tim, Your quote there is mixing apples and oranges and I won't get into explaining why none of it applies. V type engs have a totally different method of balancing whether split throw or not. Torsional oscillation, natural frequency and node damping, etc, etc. All shaft types utilized on this Stovebolt Forum will have ctrwts mainly to deal w/ secondary forces. The 120 degree jrnl phasing can deal w/ primary forces when component wts are ck'd. There's much more to it but we're not writing a book here.It has always been that the "L" meant side valve or flathead as I posted. An old Briggs and Statton flathead is an L head. Yes, they did make them with overhead intakes and a flathead exhaust. That configuration is called "F" head. These different arrangements and many others have been around since the 1870's. Some don't even have valves or camshafts. David
