i know my '69 428 built for propane will blow the doors off any stock production truck but i only use it for fishing and hauling things around as it get 3-4mpg. the only way the masses could run propane is fi ford and chev made factory propane vehicles. but napa and them wouldn't go for it as the engines last too long. i can't till you how many times my odometer has gone around. my plugs last forever too