I've put 3300 miles on my Crestline since purchase.  I have tracked every fill-up and my overall average is 15.3 miles per gallon.  My odometer is GPS-verified to be accurate, so I believe this is real and honest fuel economy.  The past several tanks have all been almost exclusively highway miles (commuting to work around 65-70 MPH).  With overdrive, my tach is reading a little under 2500 rpm at this speed.  Economy on these tanks has been 15-16 MPG.  Worst tank I have ever recorded was 13.93, best 19.24 (once--thinking may not have filled the tank as full as usual).  

Does this sound about right?

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

I'm wondering about 2500 rpm at 65/w overdrive. What is your axle ratio? Is your 312 stock?  Of course, the overdrive will not help your town mpg. 

Yes, this sounds about right. I am in that ball park too.  15 to 17 mpg if I drive normally.  1964 F100 312 mild cam, 3.5 rear end T5 trans and fairly large diameter tires.  My engine turns about 2100 rpm at 70mph. I bet if we could burn fuel as it was in the day, our mileage would be at least 2 mpg better.  But does it get any better than driving behind a fine running Ford Y-block?

64F100 57FAIRLANE500

Axle is a 3.9 ratio and the 312 is stock. It’s a bit tired but runs really well. According to my calculations, given my tire size, 70 mph should come in at 2370 rpm, and that seems about right for what I see on the tach.

I’m thinking the car could do upper teens to 20 if I was driving around 45-55 mph without stop-and-go.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

2370 at 70 sounds better. I think your mileage is in the ballpark. 

292. Stock. 2.74 gear. Cruise-O-Matic. 27” tire. 12 mpg over 11 years of city driving. Can get 13.5 on hyway, but it’s always combo. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

DLR, unless you've got the "pedal to the metal" on the highway, your mileage concerns me. I would check your air:fuel ratio.

Always been that. Even with single stock 4 barrel. Dual quads,Carter WCFB’s, made no difference. I drive with a very light foot. Automatics with the heavy converter we’re always as bad even in the 50-60’s with stop and go like 99% of mine is. Exhaust is very clean. Thru bumper exhaust tips are never black or sooty..ever. I’m not going to add a bung for an analyzer. I’ve never driven a full tank out on the hyway. I also keep a log on every tank fill up which is usually every 3 months. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I've been getting high 17's at 70 MPH with my Ted Eaton 325 CUI Y-block and a 4-71 blower! Of course I'm sure the 3:72 gear and AOD are a big part of that. Longest run was from Ohio to New Hampshire and it was 17.9. Love that extra gear in the AOD.



Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Moonshadow, is your odometer accuracy verified? My first two tanks were over 17 MPG but that was with a 20-tooth gear. It was optimistic. I have a 22-tooth now and its within 1% of GPS every time.

Do you know you carburetor, jetting, and cruise spark advance? Just curious!

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive