[panellax2]

Here is the concern....I average 10-12 miles per gallon. I feel like it should be at least 16-18 mpg.
I have a great condition two owner (i'm the second) original 68 Cougar. It has the original 302 motor, the origianl shift-o-matic trans (3.0), and a Holley 600cfm carb. There's about 150K miles on it with just a light tick that goes away after 5 minutes of warming up. It runs smooth. I have replaced the fuel filter and hoses. All spark plugs are new and with pressure testing nothing crazy showed up. The distributer is good with new cap and lines, and the timing is correct. It runs at about 3k RPM's at 70 MPH. Any suggestions??

 

[C Gauch]

Have you checked for a stuck caliper, or are the brakes dragging? E brake off..air filter clean..correct heat range on the spark plugs...

MPG is such a subjective thing, easily afftected by oxygenated fuel, driving style, topography, congestion, etc.

My '67 delivered nearly 22 mpg on a 4 hour highway trip at roughly 75 mph (2.79 rear), but around town I'm sure it's much lower. I could see where 10-12 city milage would not be out of the question in certain parts of the country.

 

[.:BLitZ:.]

That's about what I was getting in town with my stock '68 289 2V with C4, 3.00 open rear, near sea level. Maybe a little better than yours (around 12-14 I think). I don't always drive super conservatively though, and I haven't done much mechanical work to it other than normal maintenance. Best highway mileage I ever got was 21.

 

[ahunt191]

The 1967 Car and Driver Yearbook lists the fuel economy of the 289-4V at 12-16 mpg. Source: http://www.mustangtek.com/Library2/PDF/CD_1967Yearbook.pdf

June 1967 Popular Mechanics lists it at 16.5 mpg for the 289 and 14.2 mpg for the 390. Source: http://books.google.com/books?id=79...epage&q=1967 cougar popular mechanics&f=false

Having said that, I used to get about 7 mpg in the city and 25+ mpg on the freeway (circa 2000). I blame the poor city mileage on my double pumper, cam and my lead foot. My rear end (2.79) gets all the credit for the highway mileage. I haven't driven my car enough recently to know how current gas compares, but gasoline with ethanol does have less energy per gallon.

 

[Bad69cat]

3000 RPMs is where your fuel is going....it's about right. Changing the ratio will boost it up a few miles - running a 2.73 gear or going to an AOD - something like that. That 650 has fairly small primaries, so I don't think you will gain much but headaches if you try any tweaking on it. It's the if ain't broke - don't fix it category I think!

 

[xr7g428]

Check the vacuum advance diaphragm. It has to be working properly to get anything over about 12 mpg.

 

[C Gauch]

Bill's right - make sure your centrifigul (mechanical) & vacuum advance is working. Hook up your timing light, pull & plug the vacuum line, and bring the rpms up to 3k or so while watching the marks - you should see it advance, and where it stops advancing will be your initial + mechanical (the shop manual will tell you where that value should be). Then hook up the vacuum line & the timing should spike way up. Bring the Rpms up & they should climb further.

With a stock 289, you want to be around 6-8 initial, maybe 30 of mechanical for a total in the high 30's. Hooking up the vacuum advance allows for much higher advance under certain conditions.

The article linked below does a better job of explaining it.

http://www.fordmuscle.com/archives/2000/03/timing/index.shtml

 

[redcougar]

The mileage reported in car and driver was based on real gas we all loose mileage with the ethenal and other additives. just my .02 cents

 

[panellax2]

Thanks for the input. I will look at my centrifigul (mechanical) & vacuum advance again. I feel it's working right, but no harm in rechecking. One thing I do know is that when i replaced my vacuum hoses for my head lights there were all fossilized and cracked. I may want to go back in there and relpace all the other vacuum hoses I didnt replace. Maybe this will help the global vacuum system thus increasing my mileage......a little.

 

[RoadRacer68]

Sounds about right on the mileage...I got 22 on the freeway and about 14 around town...but that's injected, 5 speed, tons of fine tuning and parts to get there..

 

[Bad69cat]

Yep old stiff brittle hoses need to get replaced anyway - only going to cause trouble at some point. Also if you do run ethanol fuels you will not get consistent mileage.....about 20% less on 10% ethanol....which I dont think they even offer "regular" in your state do they?