Yes they made a 40cc engine (early and late versions). Also have a newer 40 called the M400. The 35 and 40 look the same. Look into the exhaust port, 1 ring = 35cc or late 40cc, 2 rings= early 40cc. Dick Bennett gas lots of info and is great to deal with, he can help you with whatever you need. WWW.Bennettbuilt.com