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 !

Yea...I installed a 1996 318 Magnum engine out of a truck , installed an R/T cam, with a Mopar Performance 4BBL intake and Edelbrock 600 CFM carb with an A-518 and with 3:55 gears for a Customer. It runs real good and I am hoping the customer gets colse to the 20MPG with it also.

I have heard of 440's with six packs on them getting 16- to almost 20 mpg.....I had a 69 GTX years ago and I installed a 6-pack and I am quite sure I got 18 with it..

This may be a bit off target but here's my take on our cars and the expense to drive them and have fun. Any of you own or ever own a boat? The pleasure of operating a boat is measured in gallons per hour. My point is this is a hobby and we need to enjoy our hobby the best we can. Maybe that means pulling the big block and dropping in a late model small block with FI and an o/d trans. Still get to enjoy the car and get good mpg but it may not have the grunt it had with the big block. That's the trade-off we make but still get to enjoy!

Yes...there is a trade off usually unless you happen to find a combination that works for you and your car. With all the new technology that is available now, it makes it a little easier to get the most out of the older engines or retro fit our older cars with the newer engines and transmissions to get more bang for our buck!..

with my toy...it's a toy. if I can afford gas, then I go play. if I can't buy any gas, then I don't drive it.


lucky for me, it's VERY mild right now and gets good mileage.

what I'm currently driving around as my toy is a 98 regular cab dakota, 5.2L 5 spd, 2wd, 3.92 gears with an LSD. heads are shaved to up compression, it's got a 220 duration cam with a 114 LSA, 3" exhaust, and a custom computer tune on the factory PCM for the EFI.

I estimate it's around 300 hp right now, not blistering fast, but in this truck, it's enough to have fun with and make it an enjoyable ride. I can go WOT in 2nd gear around a corner and get the back end to slide out on me.

and, I'm getting 17 MPG on the highway...in what has to be nearly 4000 lb truck. --my other 98, a club cab, with a V6 weighed 4000 even with me in the seat, and that jumped up to 4200 when I had a big block with aluminum heads, intake, water pump housing, in it, so I figure this Reg cab V8 with iron heads is probably within a few hundred pounds of 4,000

Sweet Ride...and you can haul stuff too!..:)

I won't be hauling too much with it! It's got drop springs on it, so it sits 2" lower up front and 3" lower in the back. I bet if I put more than 500 lbs in the bed, it'll be sitting on the bump stops, when my old V6 dakota has had up to 1700 lbs in the bed and was still driveable 15 minutes across town

I've got a motor in the works though...I don't think it'll be getting 17 on the highway anymore! 360 with a .030 head shave, 1008 fel-pro head gaskets to bump up compression considerably, and a nasty NA cam that's 230-ish duration on a 106 LSA. my engine program writer says he should be able to write an engine tune for it, but we may have to keep it in open loop full time, because the amount of overlap will drive the O2 sensors crazy, and the PCM might try to lean it out too far at part throttle cruise.

The first iteration of the Valiant ran a decent 14.27 @ 94mph.

Mild 360. 9:1 compression, stock 1.88 valves w/ 3 angle valve job, MP ignition, eddy performer (non-rpm) 318/360 manifold, holley vacuum secondary 600, headers and an MP .450/.455 cam. Idled w/ 16 inches of vacuum.

Transmission was an 833OD unit. Gears 2.94, open diff.

On long hwy trips for which this thing was great, it usually returned b/w 20-22mpg, with one trip netting as high as 24-25. This was a mpg or two better than the tired 318 it had when I purchased it. By the end, with the mech secondary carb it was lucky to get 12mpg....

Purchased a coronet w/ a 318 from a member here. Stock long block/heads w/ offy intake, MP ignition, eddy 600 with new metering rods/jets, small summit cam, headers. 904 auto backed by 2.76 gears. Ran 15.1 @ 91mph, and driving back from maine the worst tank was 17.5 going b/w 75-85mph, best was 20.5 going 65mph.

Stock long block magnum w/ holley 600 and MP ignition, stock manifolds and eddy performer rpm intake in the Little red truck 15.1 @ 90mph, mileage b/w 15-16mpg reasonably driven.

all mileage are hwy mpg's.

Thank you Chris!
Your Valiant and Coronet do quite well, and getting 15-16 with a truck is real good because trucks are about as aerodynamic as a brick!..LOL

I have a 1985 1 Ton crew cab 2WD truck with a 500 cubic engine, RV cam, Performaer RPM intake with a 750 Edelbrock, headers w/4:10 gears but the tires are tall..and I get around 10-11 MPG HWY..
I also have a 1987 D150 short box 2WD truck, with a 1970 383 Magnum engine w/performer intake and 650. Edelbrock carb with an 833 O.D. transmission and 3:55 gears and on a trip the best I have gotten is 13 mpg....

My 70 road runner with a 440 B-1/TS heads A 696 roller 8IN 5000 stall converter 4.88 gears.Gets if your lucky 5 mpg

HOW ABOUT this for a goal ? .... the ability to run 11.99 ...and get 20 mpg. And NOT with a steep OD manual trans or a high$$$ lockup OD auto trans OR super-trick converter.

A lite AERO car... with a short gear and a efficent/effective fuel delivery system.

As soon as I get settled in FL ... that will be my "mission" in life ....

Yea...pro6pakrr....Your 70 Road Runner...may be a gas guzzler...but I bet it is one fast runner at the track!

Doc...That is someting that a lot of us want...I hope things go well for you!...
Gary

So....Pale_Roader ...is you plan to eventually build a small block Magnum engine or...one of the new Hemi's?
I was going to retro fit a 5.7 Hemi into a customers car but the customer desided that it was going to be too expensive to do, so he had me build and install a 5.2 Magnum for his ride.
Maybe soon ...it will be cheeper to do a 5/7 Hemi into an older car...time will tell..

I had a post like this awhile back and got many of the same responses:
Miles per gallon?
Who cares.... want MPG? Buy a Prius!
I get 2 gallons per mile!
Blah, Blah.... The OP was trying to poll fellow members and was hoping to learn a few things. Wheres the fault with that? Anyone that can dress themselves surely knows that heavy carbureted cars will not be gas misers. It makes sense though to look and compare what others are doing to try to improve where you can. Being wasteful isnt smart if you have the capability to improve.
My combo: 1970 Charger 3850 lbs. 440 based 493. Edelbrock aluminum heads, Performer RPM intake, Demon 850 carb. MP '509 cam, 2" TTI headers. 2 1/2" pipes to the bumper. 727 and 3.23 gears. 27 1/2" tire height. I got almost 11 mpg on a 900 mile round trip with speeds up to 100 on the freeway,(briefly) around town cruising and some idling. I had a 4.10 gearset in the car before the trip. I love the holeshot performance of the stiff gears, so I plan a Gear Vendors install later this year. The overdrive will put the 4.10 to 3.19 at freeway speeds. BEST of both worlds.
I could probably squeeze 2 more mpg with my combo by switching to a well tuned ThermoQuad. Who knows... Maybe I'll consider that next year.

pro6pakrr......Well I am sure you will make your goal !... Good luck to you!...

Frankenduster ...........

Yea...this post started out not so good because people didn't read and understand what I wanted from them.
anyway..........
Yea...I have a 493 also in my 1 ton 2WD crewcab shop truck, I have a 750 CFM Edelbrock carb on it, I think I will try a Thermoquad also... I am getting about 9-11 MPG with it now...
If six pack set ups were not so expensive I would try one of those because I have had them in the past and got some real good fuel economy and the performance was also great when you wanted it!.

So...Pale_Roader ..What are you putting a DOHC into?
I had a girlfriend years ago that had a Shelby Daytona turbo II....That was impressive...

My challenger in my sig pic has a 440 with edelbrock rpm heads 9.8:1 compression edelbrock rpm cam,1.6 rockers,M1 intake 750 double pumper,headers,msd.Also has 3.55 gears with an 18 spline 4 speed.Just drove about 70 miles on wednesday and got 12 mpg.Never been able to get better than that,but I think I have way to much cam for highway cruising.But stand on it and its all smiles.

Thanks..killerbee69

Nice Challenger!.....We all understand... you just have to feel the power once in awhile... and you sacrfice economy ...but it sure is fun!...

Ever thought about a supercharger......like from the supercharger store?
Mopar Muscle did an article using a 318 and bolting on a super charger -it almost had 600 rear wheel hourse power! 11 second quarter mile times. They are now going to do a 273 and shooting for 500 hourse power and 25 miles to the gallon!

Quote;
No, thats about as far away from what i'm trying to do as you can get. 600rwhp and 11's...??? Mustangs can do that with 400 or less, some a decent amount less, and still not kill you at the pump. Besides, i've become a big fan ov naturally aspirated power. Anyone can go fast with boost...

Yes, that is what the article said in Mopar Muscle

It is expensive to supercharge your engine too, so I am going to put a tri-power on my 383 for my next build.

just finished it up about 3 weeks ago. 74 duster with reringed 400, pistons way down in the hole, small summit cam, its close in spec to a factory hp cam, performer intake 1 3/4" headers and a holley 750 vac secondary. i really wanted to run the thermoquad but it was giving me a hard time and i just wanted to be out driving it. t56 with 3.73s and 245 45 17s all around. i never wieghed it. i just took it on a 2900 mile round trip and got 19 mpg on the highway. my wheel alignment was really far out and it still needs some tuning. there has to be more left in it. i didnt want to do a full build on the 400 as i wanted to drive it first and see how it all worked together. im not going to be hitting the strip too often anymore so i built something that would just be fun. with gas prices what they are, i cant see how anyone could not factor them into a build. one thing i would like is to raise the compression when i do build it.then there ar eplenty of other options, i wonder how a long rod and short lighter piston would effect mileage, hp and torque. then of coarse there is the 451 or 496-500. i dont want a big choppy cam i want to keep a lot of torque down low in my cruise rpm with good throttle response. im not really looking to run 11s, more interested in driveabliity and an overall efficient combo with some good mpg, now if i could get all that and go 11.50 on a good day, that would be cool.

Well James,
19 MPG is pretty good for a Big block, I think I would build a mild 451, it will give you lots of torq and won't brake the bank building it.

i like the 451 idea, i did the 431 in my dart it runs good for what it is. i dont think it would cost too much more to jump up to a 4.15 stoker from 440source though. i like the idea of using a long rod with the stock stroke but i dont think there is an off the shelf piston for a 400, so the piston cost would kind of rule it out.

Yea, I would probabily build the 451...
440Source has good parts and also Custom pistons are expensive...