i have a 1996 f150 302 auto 3.55s and 32s and im wondering what u guys think headers and full exhaust, 1.7 rockers and the 4.9 or 460 air intake would add on mileage and power wise. i get 12 mpg now which aint bad but i would like a little more

 

12 MPG? Under what conditions? Sounds a little low to me. The 32's and 3.55 gearing are not helping you any.

Need to ask when was the last time you did plugs/wires/cap/rotor and filters? Never overlook the easy items!

 

The plugs, wires, filters have all been changed, I kno it needs a o2 sensor and that's probably the main reason for 12 mpg but I want dual exhaust and figured I would put new ones in when I had that done. Will it help mileage any to do the modifications I asked about, I already have the cats gutted and with a glass pack but its single til it get o the rear axle. I want to try to help mileage and get better performance. Any suggestion?

 

Dual exhaust will probably not help you, IMHO. Gapping the plugs to 0.55 and bumping the timing to 12-14-16 is a proven winner. You stated you already gutted the converters so replacing the factory y-pipe/converter is already addressed. Perhaps you have a "heavy" foot? Beyond that gears are probably in your future....

 

My foot probably is a little heavier than it neesd to be, I know my timing is at 10 so I might try moving it a couple degrees at a time and see how it does, how are the manifolds on these truck, would it be worth it to get headers and what about 1.7 rockers I've heard people talk about them, will they help enough to make it worth it

 

One of the 302's most restrictive area is the exhaust...from the ports all the way back. Freeing up airflow on the exhaust side will help. Roller rockers will add a little power and reduce drivetrain friction, but will not net much in mpg's. I think gearing and heavy wheels is probably where you stand to gain the most.. My 95 was rated 15 to 20 on the window sticker and I am in that range on mine.

 

Has the speedo been recalibrated for those tires? If not start with that since it's free, and then start saving up for 4.10's.

 

The speedo hasn't been changed since I got the truck and it had 235s on it then but my gps shows its only of by 2 or 3 mph, how do I recalibrate it

 

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Go back to 31 10.50. Thats what I did and it helped alot. The 32s drag it down. The speedo reading low is not giving you accurate MPG calculations. Your truck is probably gettine 1-2 MPG better than 12.