Hard to say. My previous car ['63 Valiant, automatic, Holley 1920, Pertronix with 3.23 rear end and 170 motor] delivered 25+ MPG on the highway. Sometimes hit 26, best of 28. I drove it 110,000 miles and averaged 20.8 MPG.

My current ride ['64 Valiant, 3-speed, Carter BBS, Pertronix with 3.55 rear end and 225 motor] is more consistent. I've averaged 24.0 MPG over the past 10 months. I've driven it 42,000 miles and averaged 22.0 MPG.

Careful driving habits cannot be ignored when pursuing maximum MPG. I never exceed 55 MPH on the freeway. I look ahead at traffic lights and coast in neutral when I foresee having to wait for a signal.

These cars can deliver far better fuel economy than one thinks.

Let the record show that it still has the OEM 44 year-old clutch, too.

Harley used (they've gone to EFI like everyone else) a 40mm CV carb for years on their bikes.

Same basic principal as an SU, but probably much easier to find (and cheaper) than a SU carb as owners replaced them for other carbs for supposedly more performance. There's alse a 44mm version of the CV (but that'll be expensive since it's one of the performance upgrades).

The 40mm CV's show up on ebay all the time.


Plus CV's are easy to tune.