I will have to measure tomorrow in the daytime. I wish the Petter AA1 diesels were as easy to find stateside as the AC1 and Lister LT1. Its a bit smaller and would work even better. Most Petter AC1's over here are fixed throttle, so more hard to find parts to make them variable throttle. My LT1 is variable throttle, just needs a cable set up on it with a return spring, wont be hard to fab that part up for what I plan to have done with the engine. Hopefully a complete fuel tank turns up, need that as soon as possible.