OK, i know that my stang wont get tgreat gas mileage, but i dont think its supposed to be this bad.
i filled up the stock 1967 tank yesterday and i've driven about 55 miles and its almost empty...wtf.... i dont have that kinda money, so what could be the problem, i have a 302->331 from 86 and i know they got like 15mpg, i dont get on it, there is a leak from right around where one of the bolts in the intake to the head could that be it?

I need some serious help, this is my first stang and i had to look for 6yrs to find it so i really dont wont to get rid of it

 

WOW!! That sucks.. My wife asked me yesterday what gas mileage my 69 would get when i get it back together and the best guess I told her was about 15-16 mpg.. She gave me the look.. If you know what I mean.. Our mazda 6 gets about 22 and my little green sunfire (aka crapfire) gets about 30.. My old 79 f100 got between 9-13.. That sucked,, but back then it was only 90 cents per gallon..

I would look into Pertronix Ignition, and maybe tune the carb ... What type of carb do you have? and maybe a cam could help out.. More money into the engine but maybe saving money in the long run..

Another thing might be to check that your guage is correct.. how much gas did it take to fill up the tank from 1/4 ?

 

86 mustang had over drive which is what got them the higher gas mileage.

My old 67 GB that had a 351w in it, a cam, headers, c4, and 4.11 used to get 4-5 MPG

As for a leak where the intake bolts to the head....what is it leaking? And yes it can contribute to poor mileage depending on what it is leaking.

When was the last time you gave the car a tune up? New plugs, wires, coil, cap, rotor.

 

I filled the tank until it overflowed and from the 1/4 it had 12gal, i have a c5 w/ c4 shift kit, its leaking exhaust. the car just had a tune up, like 1month ago the carb i believe is a weber 4bbl

If i cant fix it its gonna have to be sold or traded.

 

What rear gear do you have and perhaps you have a binary driving style that needs to be adjusted.

 

its a 7.5 in rear end....

 

What about letting it idle inyour drivewayfor awhile and see if gas is dripping down anywhere?

 

I did that check too, no leaks anywhere....it looks like im just gonna have to let it go, a 20yr old with a new house just cant afford 5-8 mpg, i dumped 3400 in the motor just to let it go 6900 on the car. well unles someone has a miracle fix i need to go trade it in.

 

Sorry if this has been asked or covered in another post...

What do you have on the motor to be eating up gas like that?

 

don't get discouraged so quickly!! I don't think that 15 mpg or a little better,is unreasonable for your car.

You need to look at your carb, it might just be too big, flooding a little, or jetted way to rich. I would think that you should get at least double the mileage you are getting now, the carb is almost certainly not right.

The stock rearend is probably around 3.00 to 1, good for mpg.

If your tail pipe has relativly heavy black soot in it, this is an indication that the engine is running too rich.