I don't have an AC-G, but I do have Earthmasters, the engine in the AC-G, Earthmaster, and The Massey Harris Pony are all versions of a Continental N-62 engine ( 4 cylinder,62cubic inch displacement). What you have is a pusher type mated to a reversed B A/C trans and we have a puller type w/driveshafts. NAPA has a fair amount of parts for them and there is a guy in Ct.by the name of Scot,who sells parts for them, his e-mail address is Earthmaster1@aol.com. These parts are not cheap! They seem to love them, and Continental Engine has changed hands several times and the last time I checked they indicated they did not supply parts for any of the older engines. Carburetors are especially pricey, so be very careful with it. There is also some interchange of parts with the N-56 engine that was on a few of the old IH 52R pull type combines. When it is built right this engine purrs as smooth as a kitten, very unique little engine.