My dad is unhappy with his mileage on his 83 flareside , 302 , 500cfm 2barrel , automatic, non overdrive , 2 wheel drive.

He went from 3:50 positive trac gears to 2:75 limited slip.
Either way he is only getting 13 MPG.
Would there be an advantage to doing away with the v-belts and going with factory serpentine pulleys or aftermarket serpentine underdrive pulleys?

He is thinking about putting a low mileage 1979 mustang 5.0 in the truck. Do you think it would be worth the time?

We also have a couple of 351 windsor options.
One is a 1995 351 windsor roller motor in a F-350. The other is a 351 windsor in a 1972 F-100. I have read that you can actually get better mileage with the windsor engine over the 302.
If we use the 95 roller motor we would like to keep it carbed. I read that this is okay, is it? I also realize that Fuel injection is better mpg but would like to keep the swap as computer free as possible.

Again would it be better to use the v-belt set up or the serpentine if he goes the 351 route?

Should we just change the transmission on the 302 to an auto OD from a 89 lincoln town car. I have also read that the OD does not fair well against a 351 windsor.


I realize this is a lot of questions and I have read so many threads on these subjects, it is overwhelming. I think this may be a clearer explanation. Any help will be appreciated.
I mentioned these vehicles specifically because we have these autos to choose from along with a few others in our field. They are good complete low mileage parts cars for us. (gotta love having your own private junkyard on a big piece of property)

 

Are the tires stock size? What kind of driving does the truck see? Has the speedo been checked against a GPS for accuracy? How is this milage being calculated? FYI.. it should be miles driven according to odometer divided by gallons to refill tank, hence the need for an accurate speedo/odo. Fuel gauge cannot be used and the tank does not need to be emptied every time.

That is a pretty light truck so it should do a lot better. The 302 would benefit from a cam upgrade and some longtube headers, the '79 mustang motor is probably less powerful with worse heads so it's no upgrade IMO. A 5.8 can get better highway milage but it'll do worse in town, and the AOD from the towncar will survive behind a 351 no problem if it's healthy and gets a shift kit, my AOD is still kicking.. 10 years later.

Belt system is your choice, the serpentine system is simple and has a spring loaded tensioner in many cases, the belts will last a looooong time assuming all the pulleys line up correctly. The V belt system is fine too just has more parts and belts.

 

He is not looking for a hot rod, just a good reliable daily driver. The motor also has the chevy style distributor in it . This was how the truck was bought. He has no problems with the changes you recommend. Thank you very much for all the info. This is what he is working with.

 

If he isnt worried about power I'd just go with the 302. There will be more little things to do/buy when swapping engine sizes. Whats wrong with the old engine? You might go throught all the trouble and $ of the motor change and get the ssame MPG as your old engine

 

I've been giving this some thought now that I got my 82 together and running.

I got a 302 RUG 4spd, 4x4. 2 Bbl Motorcraft. No A/C, no air pump or cat, flex fan on the front.

The best MPG I've EVER gotten was 15 MPG on runs from Georgia to New Jersey ... I was feather footin' the throttle ... keeping it to about 65 MPH. But I could get that almost every trip.

Now that gas is going up (AGAIN!!!) I'm thinking of things I can do to get a little more MPG's.

Maybe a windage tray to reduce parasitic losses in the low end. A better air cleaner set up might help.

Maybe build up a set of heads ... match the intakes and exhausts ... new set of valves ... light polish.


I don't know if a cam, an intake manifold and a Holly 4 bbl will give me a boost in MPG that would be worth the investment in money.

I really do not want to get involved in F.I. on this truck. Its built to be simple ... reliable ... easy to work on in a difficult environment.

What else can you do to a 302, without ripping it apart, that will give you an improvement in MPGs?

 

I'd just put in the AOD & ride on.

 

Check it against other same set up trucks. A friend had a 6 cyl that was geared a lot lower to make up for some power and it cost his mileage. I'd check the basic tune up items. Is the carb working up to snuff? Is the Catalytic plugged? PCV or EGR valve? Inflating your tires to the max recommended limit helps. If it were me, I'd either go with a new carb or an overdriven trans before swapping a good motor. Adding the roller cam & rockers from a mustang would help.

THere is a vid on youtube about a guy who was able to up the mileage with a few simple tricks, but that was with a newer fuelie car that he shut off when at a stop for more than 10 sec.

 

an overdrive trans will help.my 81 302 3.00 rear with the 4 speed od i get real close to 18 mpgand i drive it like i stole it.this was done with a gps,cause speedo does not work.if i leave it in 3rd which is 1 to 1 i'm lucky if i get 15 mpg