Even at its current age we still have spares for it as they are mostly the same as the current spec engine. The only problem is the head bolts. I do not expect it to need anything though, and it should be ample power for the Ercoupe. I would suggest an 18x8 prop to start off with and a 20x6 if the 18x8 makes the model too fast. You should expect about 7500-8000rpm on the 18x8 (depending on fuel/brand etc) and idling rpm below 2000. On board glow is not required and if a cylinder drops out its just letting you know its tuned incorrectly and wants a tweak!