Ouch!!
 

Got my 66 mustang running, bought it a couple of years ago in Iowa. I don't know much about cars but I was told it has a 289 with a raised cam, it had a holley carb on it which needed work so I put a 650 Edelbock on it, The cars seems to be running good,nothing coming out of the exhaust, I baby the car, easy driving etc. 2.7 rear end it it. The only drawback is that it took 32 litres of gas for 160 miles!!! That's something like 8 MILES TO THE GALLON!! that wasn;t bad in the sixties when the gas was 39 cents a gallon but at this price I can;t afford to drive the bloody car. Anyone have any ideas what my problem could be? I'm not expecting miracles but I should be doing a little better than that.

You don't mention stick or auto, but with an original trans from that era and 2.7 axle ratio, it's probably lugging the engine quite a bit. Any idea on cam specs? Anything much bigger than stock is going to need more gearing to get the engine up in to the usable RPM range. A 500 cfm carb would probably be a better choice too. What intake manifold and exhaust are on the car?

Give us some more details if you can, but to me it sounds like a mismatch of parts in the combo is likely causing the problem. My 4,200 lb. 66 T-Bird with a 390-4V and 3.00 gears gets better mileage than what you're seeing!


cheers
Ed

I had a 68 mustang convertible, auto, 289, in the 70's and I got around 20+ mpg. You should be getting something similar if not more.
Did you need to set up the carb at all when you installed it. The 650 edelbrock may need a idle adjustment and rich/lean adjustment. It should have come with a dvd and booklet to adjust (or check out the dvd segement on youtube). You may want to have a mechanic take a look at it...may the advance also may need to be adjusted.
Good luck....It will be a fun car once you getting it right.

Hi Ed,
Thanks, the car is an automatic, I have no idea what kind of cam is on it, I,m not mechanically inclined at all. The car is not sluggish at all, as a matter of fact it takes off like stink, runs great, really peppy, You're probably right about the mismatch of parts, everything else was mismatched so it wouldn't suprise me at all. I just wish I could find a good Mustang mechanic around here (Muskoka, central Ontario) everyone I've dealt with doesn't seem to have a clue about the older Mustangs (No Mustang club around here either as far as I know). I might try to borrow a used carburator in the spring and try it for a few weeks see if it makes a difference.

Call Paul at Paul Silva Performance. He has been working with Ford engines for 25 years or so and may be able to help you. He does a lot of newer stuff and the older 5.0L and I'm not sure about the 289's but give him a call and ask. Can't hurt. He is located in Toronto though.

I would love to get 20 mpg!, I had a mechanic instal it and set it up, like I said, the car runs great. I probably went overboard on putting a 650 carb on it. I wonder if anyone has any suggestions as what good carb would be that would give me better gas mileage. I baby the car so I don't need a big carb for power. Do I even need a four barrel?

500 cfm Edelbrock AVS ...

Edelbrock.com - Carburetors & Accessories - Thunder Series AVS® Carburetors

Check out the Edelbrock website or call their support number. They will let you know what you need for your use.

But if the original poster doesn't know what parts are in the engine, Paul Silva or Edelbrock are going to have a tough time giving him much help.

I simply suggested a 500 cfm carb because a mild 289 with an auto trans and highway gears is never going to see the revs to require more cfm than that.


cheers
Ed

I'll give that a shot Ed, tks