Jack: The initial Buick V6s, Kaiser V6s and GM (again) prior to late 1977 were odd-fire engines. Instead of firing every 720/6 = 120 degrees the firing order was staggered 105/135 degrees so rods from opposite banks of the engine could use a common journal. This caused objectionable vibration so the fix was to use a heavy (90 lbs) flywheel on manual transmission cars. Automatic cars had torque converters which when filled with ATF are about this weight so nothing special was required with them.
My Commando has a Delco starter that looks like all the other Buick V6 starters I have seen, but on the other hand, my Commando is a 3 speed and not an automatic.
