Performance car...fuel economy....what do you get?

Hello all fellow Moparts members!...I had some of my friends over this weekend and we got into a discussion about todays rising cost of fuel and our performance cars and what we can do to them so we can enjoy them with out taking out a loan for gas...
I thought I would put a post in here and ask all of you no matter what older performance Muscle car you drive.... ...Tell us what year and model car you have , what rear gears you have, what transmission and engine and what you engine combination is,(cubic inch,what heads, cam type, cam size, intake, carb..tec. and what fuel economy you get traveling on the highway and any other information that you feel makes a difference on your fuel mileage. Thanks for taking the time to post!...

It's smiles per gallon! :-) maybe buy a Honda!

Keep your foot off the loud pedal,but..that's no fun!!

I guess I din't make my post clear enough?
O.K.
One of my friends has a 1970 Dart with 31" tall tires, 15" wide and with 3:23 gears...727 automatic and a 360 Mopar performance crate engine -not sure on cam size but has an airgap intake and Holley 750 carb-(calabrated) and when we went to the Mopar Nationals last year on the higway gets aprox. 16-17 mpg
My wifes 72 Charger has a 3:23 rear 28" tall tires with a 727 transmission and a stock bore 400 engine with a 1963 2 4BBL intake and two 500 CFM Eldelbrock carbs ..runs good, no real power house but she likes it but doesn't get very good fuel econmy on the highway, best we have gotten is 12 mpg...

You made it clear enough, you want combos and MPG to compare and maybe a little input on how to stretch the fun.

My answer is the same, I drive what I want, when I want if I have the money in my pocket to fill it.
I don't check mileage on my stuff much and I'm not driving my stuff 2-300 miles one-way either.
Guess my answer is stay close to home and enjoy the ride.

ok. 383 30 over bore. kb 162 pistons(go ahead and bash me, didn't know) stock rods and crank. eddy rpm performers 84cc cut to 72cc, stock rods and crank, block cut to where pistons are .005 in the hole, hughes roller cam, 6 pk.keisler 5spd, 3.23 posi.70 ply b body. best mpg 23.5, worst anytime i open the 6pk, but anytime you open a 6pk it's worth it. i think the 5spd and the 6pk really help with the mpg. when i drive, just crusing i always get better than 22 mpg. it will get better mpg at 85mph than at 55mph, the motor combo really starts working good at 2200 rpm.

Thank you Jim!
Is this engine in your Super Bird Clone?
Do you have any idea of what compression ratio you have?
It sounds like you have a very good combination!
I will be building a 71 Road Runner with a 383 with a six pack set up and it will be standard shift, I am going to install the 4-speed that I have for it, for now...then maybe later change it to a Passon 5-speed and it already has a set of 3:23 gears in it.

yes it is in my clone or my look-a-like. the c/r by the numbers should be around 9.7 to 10.1. the motor made 325 rwhp and 350trq. wheel speed was 140 at 5800rpm 4th gear. using the right parts you should be able to build a motor that runs good and gets good mpg. we drove the car to san fran and averg 22mpg. love the 5spd and the 383 with 6pk. different build but works great.

Driving habits make a big difference on mileage so others results are a moot point.

Yes, you are correct Driving habits do make a big difference, and with that being said... but if anyone is tring to get fuel economy they will usually be more careful about there driving habits to get the most mileage that they can. It doesn't matter if they have a Pickup truck or Muscle car or some type of economy car.

i think the question of the op has been answered. driving habits do vary, just like a tail wind or a head wind. i didn't build for economy, i built for performance. just got lucky with the mpg i guess. but with what is known today and new parts you should be able to build for performance and economy if you want to.

My Barracuda has a 440, which was bored .030" over, and the block and heads were both milled .020". I have an Edelbrock manifold and 750 carburetor. I am not sure what my compression ratio is but the engine has flat top pistons. I didn't build the engine. I took it to a pro. The trans is a Passon Performance Hemi 4 speed with O/D. I originally started out with 2.94 gears (did not have O/D then) but switched up to 3.23 when I got the trans. This makes my final gear ratio in O/D 2.58. When funds allow I am planning to go up to 3.55s. I use MP electronic ignition with vacuum advance.

I know most folks like to just drive their cars locally which is fine but I really enjoy taking the car on long trips to Chryslers at Carlisle and the MoPar Nationals. I've taken this particular car once to Carlisle (180 miles)and twice to the 'Nats (500 miles). My best consistent gas mileage has been 13.8. This was before O/D with the 2.94s. I didn't notice much of a difference when I got the overdrive except one time I got as high as 16 MPG. I am now concentrating more on tuning the engine. Recently I have changed my timing and I plan to change the jets in the carb. I feel I may have it too rich.

A few years ago at the 'Nats I ran into a guy from the Chicago area who was basically doing the same thing as me except he had the factory Chrysler O/D trans in a Challenger with a 440. We all know those transmission can't handle a lot of power so I guess he just babies the car. He also had aluminum heads with fuel injection. I forget what rear gears he had but he was consistently getting 20 MPG.

I would love to race the car a lot but my budget just doesn't allow it. I did race the car at Englishtown a few weeks ago and it ran pretty slow but mostly because of my inexperience and know how of how to race a car like this. I won't say my embarrassing ET but my reaction time was great at .522 and my MPH was 92.8. I think if I could get good traction that would put me in the high 14s which is good enough for me.

Maybe down the road I might consider going with fuel injection but over this winter I plan on installing AC for next summer. Sorry for rambling on but I am very interested in getting a balance of performance and gas mileage.

Someday I want to make that Hot Rod Power Tour.

BTW, how did you get that Challenger hood on that Charger?

Just remembered. All MPGs in the above post are highway. Around town I usually get somewhere between 9 and 10 MPG.

I had a 10:1 .030 over 340 in a duster with 3K stall, 3:55 gears, 25.5" tires, mild head work, mild cam, thermoquad, ran high 12's. pulled 13" vacuum. Got 20MPG when cruising.

I dont think it would be too difficult to get 23 or better with a manual trans (or maybe the right converter) and a good combination of SB parts and still be in the 12's.

Philip,
Thanks for your information on your driveline set up in your Cuda. If you rejet the carb, you may see more gain in performance and fuel economy.
Thanks again!

Hay Jeff!
Thanks for your post, I have heard of some 340's getting good fuel economy....I had a 73 Cuda with a 340...4-speed with 3:91's and I tryed a couple different carbs, but the best I could get was about 15 MPG...using a Thermoquad..

I would stay away from 8:1 motors if you are looking for MPG, and 3:91's. 15 isnt too bad for that combo.

I like to travel in mine also. '70 Challenger, 496 B, Ed heads, 10.2 CR, 243@.050 MM 108 CL cam, 5 speed with .81 OD, 3.23, 25" tire, fuel injection.

I get 14 MPG highway @ 75 MPH. I've leaned out the cruise AF some more and trying for 15.

Ooops...I forgot to say that the 73 Cuda 340 engine wasn't stock. It had a set of "J" 360 heads..that were shaved ...Edelbrock LD 340 intake and the rear tires I think were 29" tall...

Andrew..That's pretty good for an almost 500 cubic inch engine!....Hope you get the 15 MPG !

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I guess I din't make my post clear enough?
O.K.
One of my friends has a 1970 Dart with 31" tall tires, 15" wide and with 3:23 gears...727 automatic and a 360 Mopar performance crate engine -not sure on cam size but has an airgap intake and Holley 750 carb-(calabrated) and when we went to the Mopar Nationals last year on the higway gets aprox. 16-17 mpg
My wifes 72 Charger has a 3:23 rear 28" tall tires with a 727 transmission and a stock bore 400 engine with a 1963 2 4BBL intake and two 500 CFM Eldelbrock carbs ..runs good, no real power house but she likes it but doesn't get very good fuel econmy on the highway, best we have gotten is 12 mpg...

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Very similar mpg on my old smallblock! I'm sure I could've tweaked it into the 20's pretty easily.

My 440 used to get 14 mpg tooling along at 70mph with 3.23 gears. Had a mild cam, headers and stock intake. 9.5:1 CR.