gas milage

recently invested in an 87 f-250 longbed w/302c.i.d. efi and all i can get out of it is 10 m.p.g. highway, what can i do to get better fuel mileage.
this truck is bone stock so i'm open to any ideas.:confused:

If it's an auto transmission, I would highly suggest a shift kit.

First thing is to make sure that engine is working at it's peak. Get a code scanner and read any error codes that might be stored in the computer. You can pick them up at any local auto parts store for about $30. Fix all codes before going on to anything else. Replace your oxygen sensor/s. If they havnt been done than it might cost you about 10-15% on your mileage. Do a complete tune up....cap, rotor, plugs, wires, filters, etc. Watch out for tire size if they have been changed. I use good quality radials and forget the big tire BS as I'm on the highway all the time. You should change the front and rear differential, transfer case, and transmission over to Amsoil synthetic oil. You'll notice a big difference with the synthetic. You can change the engine oil over to it also if the engine doesnt leak or burn oil. Its imperative that when using synthetic oil that you make sure nothing leaks as the oil is expensive. Use synthetic grease in your wheel bearings also. Clean up your throttle body, check to make sure that your exhaust is not partially plugged. Check the PCV system and filters. Buy a factory service manual so that you know exactly what to maintain and when. Some used and new ones are usually available on the web. Once you get everything that is stock on your truck running good than you can play with all the aftermarket add ons. Hope this helps a little. Regards-Stevo

Checking all that stuff is good but it can be expensive. Try adding 18 inch glass packs and headers also to your exhaust. I really dont know how they work but indeed they do. cause I had a 1984 f350 four door truck. with a 460 and a holly double pumper 850cc on top of it. i got 4 miles to the gallon at max! I was told to use 18 inch glass packs and headers to make more gas milage. and well what do you know it worked. I got it up to 10 miles to a gallon. and it sounded nice too :D

copen45, the purpose of my post was to ensure that the engine is in TOP shape before any mods are done to it. It would not make sense to add dual exhaust, headers and glass packs to a tired or sick engine...would it? What if the engine only had 75# of compression? Sounds like your 84 had way too big a carb on it which is normal in the aftermarket. I had a 69 charger with a 440 rated at 400HP and it had the stock factory carb on it which was 740 CFM. The car would do 135MPH and get 17 miles to the gallon when doing 55MPH and it was stock. My 72 Pontiac has a stock carb on a 455 and it gets 18 MPG and still do 120MPH. When you installed the headers on your truck you leaned out your fuel mixture by increasing air flow. If you would have changed to a smaller CFM carb your mileage would have gone up even more. With carbs, bigger is not always better. When making engine mods you also have to consider what state you reside in also because of emission laws. Regards-Stevo:flash:

stevo I come from a small town in west texas so it didnt matter if i ran open headers or not lol. i do know the i could have put the smaller carb on it but.......... i liked having a large carb on a large motor. it just sounded right. plus i used it for farm work only. haulin hay and cattle. if i needed the extra gas to pull or tow anything it gave it to me. lol at least i didnt put a dominator on it lol.