My 2wd '95 F-150 has the I6 and 3.08 gears. Would 3.55 gears step up my accerlation any? I have 31" BFG all-terrains, and the 3.08's pull me along but are pretty slow in doin so. Also now it's hard to get to 85mph, would 3.55's help me there at all?
Thanks for the help

 

Yes 3.55's would help you get going or haul loads better. Top end would be revving higher, but then you have larger tires also. I have 3.08 also, but in 4wd. I wish I had 3.55's since I do a lot of hauling and little highway driving. When I am on the highway, I don't usually push it past 70. The main downside would be a small decrease in gas mileage.

 

yes..i have the 3.55 but i also have 30" tires. acceleration is "brisk"

 

I have a 90 F150 2WD, I6, with a 3.55 posi. The truck is in good mechanical running condition. The truck has decent low end torque but takes a long time to get to 75+. The truck runs about 2000-2300 rpm at 75. The gears should help you get your truck going with the larger tires. If you do a lot of in town driving the higher gear ratio will improve your gas mileage. Highway it will suffer. I wouldn't go above 3.55 to a 3.73 or 4.10.

 

I own a 88 f150 w\4.9l and a 5 speed and 3.55s. First gear is like a granny gear, great for towing and pulling stuff but useless for normal drving. I usually start off in second. Around town gas mileage is 12-14 depending on the weather, the colder it gets the lower the gas mileage. Highway milage is 19-20 mpg going 70 -75 mph.Taking off from a stop is kinda slow going (it sucks) until I get into fourth or fifth. Once I'm in fifth gear truck has no problems getting up to 85-90 mph.

 

Well guys, I have a 2WD Bronco (not sold in North America) with a carbed I-6 300, 3.08 gears and a C-6, all stock. Take-offs are not so bad especially after a green light but top end acceleration is kinda crappy. Even though I have the high gears, and 29-inch tires, my mileage sucks; 9MPG city, 11-12 Highway, with everything running fine, tuned up and all... I've been constantly advised to upgrade to 3.55s yet mileage is one big problem with my truck (might as well get a 460cid and get 2MPG better or so!), so I'm a bit weary of the swap. Where I live we've got a lot of hills, plus 8.000ft altitude (not much oxygen) so I'm considering additional mods like headers, carb, porting & polishing head and increase my ignition voltage, but I wonder how dramatically is a gear change going to affect me?, I already have the gears secured 3.55, 3.73 and more if I want to, but in general the truck is quite sluggish with those 3.08s. I've been surveying here and guys with V-8 equipped Broncos are getting better mileage even with the same 3.08s!, I though the six was the most "economical" or the "least gas guzzling" of the Bronco small blocks....! I wonder if a wild cam would help too...?

 

i would bet that with 3.55 your city mpg would actually improve slightly. Much less gas pedal needed to accelerate the vehicle.

 

With 3.08, I wonder if ya'll are "lugging" making the I6 work harder then if ya'll were running 3.55 gears.

 

Gas milage takes into consideration a lot more than just rear gears, but they can help. Like mentioned before, are you lugging the engine a little too much?

 

I bet you'd be better off with the 3.55's or even the 3.73's, but since your only runnin 29"s id say 3.55. I have a 93 bronco 302 and 270k and reciently put on some 33's and notice driving up hills is a little more demanding than before. Since you said you have lots of hills i bet you're workin your pedal too much to keep her goin up the hills just like i am with the taller tires. Lower gears will help alot.

 

Short of anything better than 16 MPG on the highway, I really like my 3.50's/31"s. I've got power to spare at 75 mph in 4th. (Stock rebuild, EFI/Clifford/Holley 390, P&P, 1.65 rockers ).

75 to 85mph, in maybe 5-6 seconds.

You didn't mention what tranny you have, 4.9...

 

yes, tranny makes a big difference.

 

I have the I-6 too, and get real crappy milage, like 12.5 on a nice day. It has a C-6 tranny and 1 barrel carb. I was thinking maybe I need a 3.55. Right now it has the stock 2.75 with P235/75R15 tires. It dosen't matter if I pull something or trun on the A/C, it's still about the same.
Any comments on that?

 

Hey Sgt.Wonderful, I have almost the same set-up; 87 F150 4.9L EFI, C-6 and 2.76 axle. I get 16 around town and 20 on hwy. 118,000 miles. I just had original muffler and tailpipe replaced,had 2 and half inch pipe run from Cat all the way to back with no muffler. Sounds like Dodge Cummings Diesel at tailpipe now; but most of all it has more pulling power on hills and much quicker throttle response. I guess because of less back pressure. Very happy with it. 300's forever!