Ken I don't know about the MPG, but have heard that this engine is way under powered. Not sure about anything else about them other then you need to check the exhaust manifold. They are prone to metal fatigue and just fall apart. VERY,VERY, VERY, VERY,VERY,VERY hard to find in useable condition. Andre " A.J." Jacobs, web page http://southtexasamc.tripod.com (830)-980-3165 , akjamc@xxxxxxxx Owner & Proprietor, South Texas AMC