OK everyone - - - - What seems to be the general experience on MPG with your rigs? I'd really like to know if any of you is getting >10 MPG.

Matt

I can get 12-14 in my Brougham cruising at 60 mph but it's a bit lighter than the GTC and has a Thermoquad which is better on gas than a two-barrell (untill you open those giant secondaries).

I haven't driven my GTC enough to know what the mileage is but I have an old ad from the '80s that says "Two weeks ago we traveled to Las Vegas and averaged 11.2 MPG going (trying to stay at 55 MPH) and averaged 10 plus on the return traveling at 60 to 62 MPH".

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Nick Taylor - Green & White 1974 Hall GTC.
www.NicksGarage.com == www.HallGTC.com == www.NicksTeardrop.com

Great MPG on the Brougham, Nick. 60 is hard to maintain when you have so much power available! As you know, I replaced the original equipment on my machine with an Edelbrock spreadbore intake, squarebore adaptor, Edelbrock/Webber mod 1400 4 barrel carb and stainless steel headers. I also had a new exhaust system from the headers back with 2.5" feeds going into a flowmaster with 3" tail pipe. And a resonater to try and cut back on the incredible racket. I did all this not be be a hot rodder (well, maybe a little), but to give better performance in the mountains and better MPG cruising. Because of the speedo reading 8 MPH fast (!!) I'm going to have to use an old GPS that reads MPH to get a true reading. Short of pulling the transmission apart to change the drive gear, I'm not sure what else to do!

You didn't say what mileage you're getting and what conditions. I'd assume it's less than 10 since you're asking if anyone is getting better than that.

I did use a GPS tripmeter to get an accurate mileage. My speedo is right on but my odometer is fast. Which actually means that my speedo is slow but falls in the right place. I'm using slightly shorter tires and using the cruise control on the highway to maintain 60 because it wants to go 70.

I looked at overdrive solutions but the expense would take a long time to pay back. You could also change the rear axle ratio. You'll lose some power at launch but will be better on the open road. I figure in the Brougham I'd do better with around a 3.50 ratio. I haven't priced that out.

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Nick Taylor - Green & White 1974 Hall GTC.
www.NicksGarage.com == www.HallGTC.com == www.NicksTeardrop.com

I'm guessing around 10, but don't know for sure. I'm going up to Arroyo Seco campground this weekend, which is West of Greenfield in the Coast Range, so I might get a better idea by the time I return. I'd still like to hear from some of the others about this. I like the 4.10 rear end fine since It's way easier on the torque converter and transmission, but a nice little Gear Vendors unit would be perfect. I'll have to play the lottery.

I know I've been getting around 12 to 14 just really depends on how you drive it. I try to stay at 65 and tuck in behind a truck on the freeway. Towns and super curvy roads I probably get much less like 8 or 10.

Just returned from a camping trip, once again getting around 10. Combination of freeway and twisty mountain roads I had a full 50 gallons of gas and water on the way there, close to 800 lbs) , lots of gear and supplies and 2 humans and a dog. Had a mild tailwind on the way home and seldom went >60. I agree that 60 is where it seems the most in the groove. Having a new engine it used no oil - no leaks anywhere, actually. I feel pretty comfortable about letting it "attain speed", rather than show how fast can go, but it's still calling my right foot . . . . . . . . . .

Do you think your mileage will go up once it's fully broken in? Are you using the cruise control? Maybe fill up with water closer to where you're going.

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Nick Taylor - Green & White 1974 Hall GTC.
www.NicksGarage.com == www.HallGTC.com == www.NicksTeardrop.com

im getting 10 + all day long...i must admit i have not done much city driving ...all open roads and highway...but its oki...and thats with a poor old exhaust ..im working on duals as we speak

Town driving will drop the average way down, as will mountain driving. When I first got mine I was getting around 8 with all stock equipment and dual exhaust. With a new engine, transmission, headers, Edelbrock intake and carb, 3" free-flow exhaust, tires as hard as I can stand it and the timing as close as I can get it*, I THINK I'm getting around 10 on the freeway. Head and/or tailwinds have a huge amount to do with it! I'm very careful with the throttle and try to keep it at 60 +- on the road. It wants to go fast!

*I say "as close...." because the people who installed the new engine forgot to put timing marks on the new torque converter and, since it's impossible to see the marks on the harmonic balancer on these things, timing is completely trial and error - with an emphasis on error.