I've come up with a flywheel timing pointer that allowed me to set the ignition timing from the top of the engine. It clamps to the flywheel. You point one end of the pointer at the timing mark on the flywheel, clamp that position then move the prop until the other end of the pointer points to the crankcase split. I came up with this to help in timing my IO-540 with the new 6 cylinder E-Mag from the top of the engine. It can also be used for timing a standard mag. If the crank case is covered up by a baffle, you can transfer that position to the front side of the baffle for the pointer to point at.