chad.durnal

one of my family friends put a throttle body spacer on his jeep and it got me thinking of ways i can gain a few mpg. is there anything i can do to my '71 grande with a 351 cleveland to gain a little mpg?

fb72stang

Put in a 302... XD

69FB

Well if you have not done any modifications (and not sure of your budget) I'd recommend an aftermarket Air Filter and some headers/mufflers. I know it will probably not do wonders but I've read many articles on how it helps.

pushrodpower

You best bet is to either do a tune up or have an economy car tow yours.

REAVER117

Well you could install an electronic ignition system and new coil, I've heard those can help with mileage. Also you could lean out your carb or if you really want to gain some mpg you could do an EFI conversion-it's pricey but depending on how much you drive the mustang it could pay for itself within a year or two. I've heard as much as a 20-35% improvement in mpg. If you're interested check out this site: http://www.detomaso.nu/~thomast/efi/

p25486

What kind of headers will help the most?

1971mach1

Yea, get the 6 cyl engine that's being swapped on the other thread. Probably could get it cheep.
To get better hiway MPGs, go to a taller differential gear (numbericly lower). Someone here has probably upgraded to higher gears for better accelleration, swap them for their "hiway geared" differential, you want like 2.70 or 2.80. lower the better.
Another cheep and easily reversable way to get lower RPMs on the hiway is to put much larger diameter tires on the back, it has the same effect as switching to a taller gear.
Put a 2v carb on and tune it lean.
Advance your timing and running premium gas will increase you MPGs.

REAVER117

Also swapping to a T5 or another transmission with an overdrive gear will boost mpg.

tarafied1

How "little" of a gain are you looking for?
If your car is mostly stock it probably already has a 2 barrel and a 2.80:1 rear axle ratio. The 6 cyl swap won't be a gain worth the money, effort and lost resale value. The other suggestions like tune-up, air filter, timing, headers, etc. will be a small gain but were talking maybe just a couple mpg. Still good ideas and worth doing but probably won't make a huge difference in your wallet.
The only major gains would be EFI and/or overdrive trans but those are costly options. Unless you drive the car a lot it would take a long time to recover the cost of the converstion. However there are other benifits to both. EFI will make the car more driveable in all weather conditions and easier to start as well as less polution. The trans swap will also make the car more fun on the highway as you will notice a big drop in engine RPM's which will also prolong the life of the engine.
The biggest no-cost gains believe it or not will probably be a change in your driving habits. If your like me your tempted to accelorate quickly and drive faster when your in your classic Mustang. You might see improvement by just driving like an old lady on Sunday!

andrewmp6

Yeah efi and a over drive will help the most but there not so cheap to do.Dumb things like watching your tire pressure and driving like a old woman help a lot.