"Ed Price" wrote
However, the 70's cars were notorious for trying to reduce exhaust
emissions
with pneumatics, thermal delays, and other non-electronic systems. Those
systems created balky, stall-prone engines, so we need to move the date
back
to about 1970.

Second that! My 66 Fairlane with a 289 V8 got 17-21MPG. My 68
factory-special GTO would just lift the left front tire off the ground
coming off the line, and charge past 120MPH, but got 12 MPG. My buddy's
1972 340 Duster was slower than the Fairlane and barely got 12 MPG. The 72
made less nitrious oxide than the goat, which was good for LA smog, but made
more half-burned hydrocarbons that the rest of the country didn't need.