Have you checked your gas mileage

[connvalley]

I've been interested in purchasing a GT/CS but I began thinking about my old cars that I drove back in the 60's. At that time, $1.00 bought me about 4 gals of gas which was a bargain for cruising around town. However, I never checked nor did any of my friends check to see how many miles per gallon we were getting at that time. Who cared, we were having fun and I was taking my date to McDonalds which charged 15 cents for a hamburger. Gas and food on a Friday night was $2, what a deal ... So now with gas nearing $3.00 per gallon or more, what is the typical mpg for some of the GT/CS engines with automatic transmisson? Anyone out there checking or are you still cruising around not paying attention and having fun?

 

[390cs68rcode]

I get about 14 mpg with my 289 motor and 10-11 with the 390. Both autos

 

[connvalley]

I believe the fuel tank on the 68 mustang was 15.7 gals. So that would mean at $3 a gallon, it would cost over $40 to fill up. Wow looks like cruising will become costly, may have to do a hydrogen conversion 20yrs from now when it gets over $10 a gal..

 

[davidathans]

My 347 motor drinks fuel...my best gas mileage with this motor and C4 auto trans with 4.11 gears is 8 miles per gallon at best! When i get on it I'd say its about 5mpg. Im using a 670 holley carb with Holley size 69 primary jets and size 72 secondary jets...it might be runnin a little rich

 

[davidathans]

When i fill up all the way, the most total miles I got to a tank was 115 miles. 15 gallons at $3 a gal is $45. 115miles divided by $45 is 2.5miles per dollar or $.39 per mile. OUch....you know this is ridiculous because these gas companies post a 8 billion dollar PROFIT in a QUARTER!!! I spend half my paycheck in gas

 

[p51]

So, on a 302J engine, when I bought my my GT/CS I calculated ~13mpg in the city, ~16mpg highway. After upgrading the performance/economy (esp on the highway) went up. Upgrades were:

(1) 5spd transmission
(2) Headers (shorty) and free flowing exhaust
(3) K&N air filter

Performance and economy both went up. I now get ~15mpg in the city and ~21mpg on the highway (but I *really* drove conservatively to get best very best mileage). The 5spd really helps out. I also understand that EFI also will give mileage a good boost.

 

[CalPaul]

I try not to look...

 

[68sunlitgold]

With my 289 I actually got almost 19 mpg on the trip down from Minnesota, but around town I am like everyone else and get around 15-16.

Doug

 

[68gt390]

Let's see - I've gotten to the point were I just pull a gas station behind me. Since modifying my engine at best, I've been able to get 9/10 miles to a gallon on the freeway with 4 speed and 3:25 gear. I can just imagine what will happen when I put in the new 3:50's. Some where in the back of my mind I think I hear the words TKO 5 speed.

Don

 

[DSO51]

Rebuilt 289, converted to a 4 barrell (autolite) and flow master dual exhaust. I'm getting 11-12 cruisin' and 14-15 on the hwy. Ok - let's call it 7-8 MPG because I rarely take it on the hwy and I can't seem to keep my foot out of it.
Love the sound of those flowmasters.

Craig

 

[Mustanger]

[quote author=P51 link=board=1;threadid=2067;start=0#msg13843 date=1124914587]
So, on a 302J engine, when I bought my my GT/CS I calculated ~13mpg in the city, ~16mpg highway. After upgrading the performance/economy (esp on the highway) went up. Upgrades were:

(1) 5spd transmission
(2) Headers (shorty) and free flowing exhaust
(3) K&N air filter

Performance and economy both went up. I now get ~15mpg in the city and ~21mpg on the highway (but I *really* drove conservatively to get best very best mileage). The 5spd really helps out. I also understand that EFI also will give mileage a good boost.


[/quote]

That's really good for a V8 that was built in '68 ! Did you ever have it rebuilt, and if so, how many miles are on it? Oh, one more, what rear end gears are you running, 3.00:1?

 

[p51]

[quote author=Mustanger link=board=1;threadid=2067;start=0#msg13875 date=1125001976]
[quote author=P51 link=board=1;threadid=2067;start=0#msg13843 date=1124914587]
So, on a 302J engine, when I bought my my GT/CS I calculated ~13mpg in the city, ~16mpg highway. After upgrading the performance/economy (esp on the highway) went up. Upgrades were:

(1) 5spd transmission
(2) Headers (shorty) and free flowing exhaust
(3) K&N air filter

Performance and economy both went up. I now get ~15mpg in the city and ~21mpg on the highway (but I *really* drove conservatively to get best very best mileage). The 5spd really helps out. I also understand that EFI also will give mileage a good boost.


[/quote]

That's really good for a V8 that was built in '68 ! Did you ever have it rebuilt, and if so, how many miles are on it? Oh, one more, what rear end gears are you running, 3.00:1?

[/quote]

Its the original engine but it was completely rebuilt ~4K miles ago. Yep, a 3.00:1 rear end. Cruising at ~65 in 5th my RPMs are (just a guess) around 2000 or so. I was pleasantly surprised at the mileage but, realize, it was highly controlled experiment. I was really trying to see the best mileage I could get out of it so I really took it easy on acceleration and winding it out in the lower gears. And the 20+ mpg was almost exclusively highway.

BTW: There was an experiment that the guys did at MustangsPlus to see the benefits of 5spd/efi. The ran a ~stock classic mustang with a C4, 5.0L engine, carb, 3.00:1 versus an upgraded classic mustang with 5spd, 340hp crate engine, efi, 3.5:1. They got an average of 14.65mpg on the stock mustang vs 20.89mpg on the modified mustang. If you get their catalog the details of the experiment are in it. Unfortunately, I dont think the info is on their website...

 

[Perkchiro]

Well, after reading all of your posts on this subject, I am going to purchase a car hauler and pull mine with a truck that gets about 16 mpg. How"s that for good gas mileage? 8)

Steve

 

[hookedtrout]

[quote author=Perkchiro link=board=1;threadid=2067;start=0#msg13900 date=1125027659]
Well, after reading all of your posts on this subject, I am going to purchase a car hauler and pull mine with a truck that gets about 16 mpg. How"s that for good gas mileage? 8)

Steve
[/quote]

That's kind of what I did, however my truck (Super Duty V10) only gets 11 MPG pulls the 25 foot toy hauler like it isn't there however. The Expedition would pull the car hauler I'm sure and it gets a little better mileage so I guess I do have a little option.

Hook

 

[davidathans]

The MustangsPlus Article discussing the C4 trans vs 5 speed and carb vs. efi was really interesting. Nobody has mentioned anything about gas mileage with an AOD trans...just curious what kinda gas mileage one would get with that and whatever engine/gears...?

 

[Sarge]

I measure mine in "smiles per mile", not miles per gallon. ;D

But if I was to guess, I would say about 10-11 in town and 13-14 on freeway (if I keep my foot out of the carbuerator...hard to do!!!)
Robert

 

[meadowsdk28]

[quote author=Sarge link=board=1;threadid=2067;start=15#msg13914 date=1125073632]
I measure mine in "smiles per mile", not miles per gallon. ;D

But if I was to guess, I would say about 10-11 in town and 13-14 on freeway (if I keep my foot out of the carbuerator...hard to do!!!)
Robert
[/quote]

Well, there you have it. Totally agree. I drive a stupid KIA for MPG's.

 

[Mosesatm]

I wonder what a kind of mileage we'd get with a modern V-6 (Maybe a Nissan) that pumps out 285 net hp and modern manualmatic? ;D

 

[meadowsdk28]

Here we go with the Nissan thing again!!

 

[68gt390]

Nissan's aren't all that bad. Heck, up until last Thursday I drove a Toyota Camry for gas milage. Seems I had an encounter with some deer and a tree. :'( Guess who lost that battle. Anyway, now my GT is a daily driver once again. At least until I get the Camry back from the body shop. I sure hope that happens before the first snow.

Don