I, like a lot of board track builders wrestle with trying to make a engine look vintage or fill the space to make one look more period correct. Here is one that I done using a antique Quincy air compressor for a engine https://www.youtube.com/watch?v=DRF0fMNM1zg and this is the one I am working on now, it will be 280cc and look period correct for the early to mid teens. https://www.youtube.com/watch?v=wh4UWOD8WiE&t=4s I am building the engine case from wood, then casting it from aluminum. The cylinder is a WW2 B-29 APU engine cylinder.