Roy, forgive me I'm a canuk we call them stoves up here but your right he only uses the oven part!
Semp, I checked out that site,
I'm not sure where they got their figures from but those are rather generous! I and my family owned or drove most those cars on the list and I cantell you from real world experience that there were few if any cars that got 40 mpg never mind 60mpg.
Most those cars used a carb and only afew had any type of computer controlled ignition. Try any NA built car made in 74 and shut the engine down! See how long it runs on because of preignition!
My wife had a 74 nova and you had to turn the key off and let the clutch out ingear to stop the engine from running on. they got better about 76 when they figured out how to stop this issue but it wasnt until the added fuel injection and comp. controlled ignition that the really fixed the problem. They ran the cars too lean to pass emmisions,pump exhaust gases back through the system to reburn the mixture and this cause carbon buildup and thats what caused the run on issue.
I'm sure the more technical guys can chime in and explain it better or even add their own real life experiences with 70's(mid to late} and 80's cars! 1974 was the year they stopped building anything with power,check the hp on even the vet that year!!!!
Oh and find me a car from then that gets 50mpg and I'll pull a klinger and eat it!