Rob C - Nope no lock up trans, standard 727. Tires were 235 75 15.

Good to hear that some are getting 20 or more mpg. That is encouraging

Yea, it's possible to get 20 or better mpg's out of your 360 though a high performance mill is not going to be. Some of the things I didn't do that are supposed to help get you mileage I didn't do. I wasn't hunting for mileage. The best I ever got was 22 on the Hwy. while traveling from New York down to Ga. Gasoline seems to be better off the Long Island. Cheaper and a better bang for my gallon. But to say I would get 22 is not accurate. 20 was the best I could achieve on a regular bassis if I drove it easy. (Speed limit or there about. Not 70+mph!)

At the time, I needed to have cat's on the car. I didn't want to use the standard 1 size fits all headers that are going to get wrecked on the first speed bump or pot hole. Dougs and TTI's were to much for my pocket. But I think headers would have helped just a little bit. My exhaust was 2-1/4. Twin cats and Thrush Turbo mufflers connected with an H pipe done at a muffler shop. Considering the low power of the '79 mill, I'm not to sure if a 2-1/2 exhaust would have helped.

The Fed-Mougal 625 Carter carb was well tuned. I would have liked to try a TQ. The idea of the smaller primary for a higher velocity charge. Good for atomizing the fuel. Good on low rpm mileage hunts. The perfect match for the factory iron intake. Which there pretty darn good intakes. I did think about trying 2 other intakes though. A Performer and a LD-340. The Performer would have added velocity. The LD-340 is a high rise, large port via compare to the Performer. The Perdormer for high velocity and the LD-340 for having the large port for the bigger C.I.D.
I'm still not sure which one would be better.

With the low compression of the engine, I could not see installing a set of closed chambered heads or a cam. (More of a money issue at the time.) The size of the cam would not be to large. Since mileage was the idea. Just a split duration cam to help. The idea of getting a better cleaner intake charge. A few more degrees on the intake May actually help. As long as there is an increase in torque in the rpm cruising range, mileage could increase.

Most everything is in the tune. Not just the carb but also in the distributor. The whole engine must be looked at and maxed. Then of course, the rest of the car comes into play. Balancing the tire size with the gear ratio in the cruising rpm to keep the engine rpm at or in a high torque area of the engines power range.

I'm not sure if the 904 I had was a lock up. But a LU is known to add a little bit of mileage. I only gave the trans a deep pan.

(As stated earlier, I didn't have the funds to tinker around. Which I love to do. House & family are first, tinkering & toys later.)

Rob C, I agree with what you are saying. Attention to details can go a long way. Good carb tune, a good exhaust, and definitely working with the ignition timing, mechanical and vacuum advances are a great start. If I were to end up with the car I hope to go look at, I might later on consider a MP stock copy aluminum intake and a 500 Edelbrock AVS, which have rather small primaries. Then with a reasonable rear gear and careful driving 20+ mpg seems likely, yet quite peppy when needed, or wanted, LOL

Mike you should read about what I did with the Cuda and one of the engines I built for it

https://board.moparts.org/ubbthreads/show...e=4#Post3944014

HRDave, it's bee a while. First of all, where is the Cuda these days? And how's that weather up north?
Actually I read that article not long ago with great interest, and will read it again (and again). I know the guys with the slant sixes work a lot with ignition timing and mech/vacuum advances to get the best MPG and power/torque out of them. Those are especially important with low compression ratios.

I had to sell the Cuda to pay for to start my new buisness about 4 years ago. It is now in Hawaii.

Weather here has been warm then cold, swapping back and forth several times over the last month.

I would think a 360 with some KB107 pistons in a 5.9 magnum with a well tuned thermoquad could nearly equal what I did if you work hard on the tuning and a good high gear ratio.

And about gear ratios, I have not really found a low ratio to help any in town. I used to think it would but none of my testing on many different vehicles showed they got better MPG with a low ratio in town.

Dave, what kind of business do you have? That green you had the Cuda painted is a good fit for Hawaii.
Interesting results concerning gear ratios for around town. So, it's best to chose for the highway and let the town take care of itself, eh?

87 Ram

Had a few different combos in this Ram.
Started with the original 318, 904, 2.76 gear. Low 20's but extremely gutless and could not tow.

Swap to a carbed 360 Magnum. 518 auto and 3.55.
16-18 and a best of 19 straight highway.

Lost OD on the 518. Still getting 18mpg but had to drive 100km/hr. With OD I was cruising at 120km/hr.

Best move was a swap to a NV3500 5 spd manual. Big gains in mpg. The OD ratio was similar but it was way more efficient. 23mpg straight hiway.

On the Skyway bridge here. I used to switch of the OD on the 518. With the manual trans, I could easily climb it in 5th. I also gain mph in the 1/4. 90 with the 518, 93 with the manual.

The 518 or 727 is not near as efficient as a 904 or a-500. I have swapped several vehicles from the big one to the small one and there is a very noticeable change in power and MPG and I almost never have to rebuild a-500s. However a manual is even better

I wish there were readily available 3.23 gears for my dakotas front diff, I think that is about all the little V6 can handle. I currently get around 20-21 average in mixed city/highway driving. I have 3.55 gears.

For mods it has an electric fan, 205 t-stat, o-20 synthetic oil, advanced the crank sensor, cold air intake, V8 throttle body, 3.3 injectors. I just switched to very tall tires, the MPG liked it but I don't.

I am planning to change out to thinner diff and trans fluids in the near future.

I shift very early and use mid grade fuel to smooth out the lugging/pinging it will normaly do when I keep the RPM at or near 1000 till I am in 5th gear.

I have never checked MPG strictly on the highway so I can't give you the really awesome numbers yet.

Look at this. You guys think I'm crazy. Here it is. 25.0. 55 mph. Over 300 miles on the tank and just under half tank. Get you some of this!

here is the cluster pic

Mileage went from 24.7 to 25.9. But was here most of the time. Don't say it can't be done cause I can show you otherwise.

1996 Ram 2500 2wd regular cab long box 3.54 gears towing a 24' enclosed with a 64 Max Wedge Plymouth in it today and I got 9.5 MPG at 65-70 MPH. Coming back north against the wind with a 72 Plymouth Roadrunner I got 7.5 MPG at 70-75 MPH.

No one believes me about the highway mileage this thing gets but it does get mid 20's at 55 on the highway. City is another thing but highway is great. I towed a 70 mustang back from Columbus to Florence and it got 15ish.

I used to get low to mid 20s on the highway with my 360 but all city was horrible, down in the single digits.