Another thought, if you have not all ready obtained a pressure regulator yet, look into getting a regular gas bottle regulator, like a Victor or Mathewson. These allow you to dail the pressure up higher, and can flow more air. This allows you to spool the engine up to higher speeds and get cooler starts, and in the end you use less air. I went to my local dive shop and they got me in contact with the company that did the repair/maintance on their compressor. That company had the correct hardware to connect my SCUBA bottle to the regulator (DIN to 1/4 npt with a filter). You could also think about using an industrial compressed air bottle, however they are heavy compaired to a SCUBA bottle.

Have fun with it.

Steven