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Gas mileage on a 170 in an a body??
https://www.slantsix.org/forum/viewtopic.php?t=43238		 Page 2 of 2
Author:  NCDemon1971 [ Sat Jan 15, 2011 9:10 am ]
Post subject:  Re: Fuel injection
Quote:
I believe Lou's Dart is fuel injected. He will straighten this all out. :D Here is the quote from Lou after the air dam was installed
Quote:
Big success with the airdam. Lowest tank was 23 MPG with 1/3 city/speed driving, highest tank was 401 miles using 14.8 gals or 27 MPG. That last tank was all hwy miles and 65-80 MPH cruising depending on traffic.
Rick
That's great gas mileage! but there's no way I can afford fuel injection :(
Author:  Dart270 [ Sun Jan 16, 2011 8:58 am ]
Post subject: 
Yes, throttle body EFI in the Dart. If I bolted a good BBD on there I bet it would give the same mileage. If I were you, I would not bet on more than 25 MPG in a 170 A-body without some significant tweaking. Easiest would be to buy Erik's car off Charlie's "lot" and have fun and mileage with it.

Don't get a '67-76 Dart with concave rear window, esp 4dr. I'm convinced aero on that hurts hwy mileage. Earlier cars better for weight, which will help mtn driving and in town MPG. 70-72 Duster/Demon would be another good choice.

170 will be marginally better than a 225 - maybe 10-20%?

Lou
Author:  Romeo Furio [ Sun Jan 16, 2011 2:48 pm ]
Post subject:  170 Mpg
F.Y.I
Stock 63 Valiant,79,000 miles, 170, auto, 2.76 rear. Daily driven mostly short trips, Start and stop the engine about 5-6 times a day.Sometimes as many as 15 times. 18/20 mpg. I hope to better it with a BBS as the Holley is on it's last legs (leaks) and has been gone through several times over 48 years.Hope the Carter works as well.
Author:  kesteb [ Sun Jan 16, 2011 8:34 pm ]
Post subject: 
I have done the 8.25 and 2.45 gears in a '65 Dart, I wouldn't recommend using an automatic, it was usable with my '64 4 speed with the 3.08 first gear.
Author:  ESP47 [ Tue Jan 18, 2011 8:11 am ]
Post subject: 
I could see a 170 outdoing a 225 on the highway but not around town...unless you live in a small town you just put put around in.

Where I live you'd have to mash the gas from stop light to stop light to keep from holding up traffic. I got a lot better mpg with a super six setup just because I could roll onto the gas and get up to 45mph rather quickly...while with my 1bbl setup I had to get on it pretty hard to avoid being passed by grandmas.
Author:  mpgFanatic [ Wed Jan 19, 2011 3:38 pm ]
Post subject:  170 and 225 data points
Quote:
I have a 64 Valiant in my yard, with a 170, that belongs to Erik (mpgfanatic). The engine was built for economy. Honest 9.5 CR, the mildest MP cam. bored and honed .060 with a block plate.

It gets 27-28mpg on the highway. I think with a 4 speed OD it would do better.
Can run upper 16's in the 1/4 mile.
All of that is correct except the 1/4 mile times. {grin} The only way that car would approach 16 is on a steep downhill with a tailwind. (It would have improved my bragging rights if I could have located a drag strip shaped like that.) On a real strip, I pulled a few mid-19 times at about 70 mph. It's easy to make the first return lane, though. ;) Actual gas mileage figures for that car are 22-24 around town and 26-27 on the highway, with timing tuned for premium fuel.

Back in the 1980s, I ran several different mid-60s A-body cars with 170 and 225 motors, on whatever 87 octane cheap stuff I could find. Rear ends were usually 3.23, and mpg numbers didn't matter much between auto or 3-spd. Mileage was always in the 15-16 range until I learned to rebuild carburetors. Then I could reliably attain the following city/hwy numbers:
225-- 18/23
170-- 19/27

For what it's worth, the 273 or 318 2bbl with either 2.93 or 3.23 gears would get nearly identical mileage as the 225 and be a whole lot more exciting to drive.

The only place I'd recommend the 170 over the 225 is on the open highway... as long as you don't plan to pass anyone up a long grade. Around town, the foot is to the floor most of the time just to keep up with avg drivers, and the mileage suffers appropriately. CAN it be driven so gently that mileage gets up to the low 20s? Yes. And it's excruciating.

- Erik
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