If you feel you "need" the 4.11 gears due to the hills, then your gas problem is your right foot.

 

Chase, keep in mind that you have a 351 and Bill has a 300- they have totally different attitudes. What part of South Carolina are you from?

 

ALso make sure you're at least using plus(89), regular(87) burns like water.

 

well i guess it is my 5.8 that is causing the low powerband on the hills for me with 3.55 gears hey bill you want to trade gears lol

 

well i am from arkansas which is why i never had a problem out of my truck but i recently had to take a trip to Canton SC and my wife is from Aiken SC I think i may go with 4.11 on mine so i can pull these dang tires on hills lol I just hate taking the rear end apart it is so much work lol.

 

jas, did I say I felt I needed the 4.11? if so, I meant to say my dad says I do. I wanted to know what you guys thought. Considering the hills, maybe 4.11 is the better choice? have you ever left texas jas?

Thanks to everyone for your replies.

 

Water doesn't burn, which means that would never run out of gas. I don't even know what you're trying to say with this. The 4.9/5.0/5.8 will see no benefit from running anything higher than 87 octane gasoline unless they have advanced timing.

 

Bill, my 3.55's liked hills way more than my 3.08's, and I would say that my truck enjoys lower rpms about as much as yours (also running 31's). I guess my question is "what is your cruising speed?" and "what kind of mileage are you getting now?"

 

My cruising speed on the highway is 60 (2,200 rpm). I keep to backroads as much as possible, which is 40 and 45 mph (about 1,500 rpm). My mileage I'm getting now is about 12 mix, with 15 highway, 16 at best. Around town kills me. I can watch the friggin' needle move.

Heck, maybe it really is my right foot. Just seems like that's the only way to get a 300 to move, though.

 

Bill, IMHO, placing a cover over the bed or removing the tail gate will do nothing for you. It's the 4.11's and the 31 x 10.50's.

My '86 F-150 4x4 had the M4OD and the I-6 and I was running 3.08's from the factory and 31x10.50's. The truck wouldn't pull well unless it was in 4wd but had plenty of hwy power. I took it to Maine several times and upstate NY once and she did fine. I averaged 17-18 hwy and slightly around town.

I'd consider dropping to a 3.55 axle and or running stock rubber if you want the mpg's. The 31's fill the wheel wells nicely and they look great and handle even better. I think the 4.11's are a little too stout for the 300 as this motor is a low rev engine and is more comfortable in the lower rpm range.

 

It would seem to me that your current gear setup would potentially hurt highway mileage, but I wouldn't think that the 4.11's would hurt your city mileage any. I would actually think that it would improve it. But I could be wrong.

Seems to me, if city mileage is that poor compared to your highway mileage, then it may be directly related to your driving habits, or something may be wrong with the truck.

 

Basically, he's full of it

 

You just weren't going fast enough. I've got 3.08's and 31's with the 351 you just gotta cruise at 90mph to stay in the powerband

 

I run with my tailgate down , but some considerate yahoo is always shutting it for me. Of course it dont do anything for the milage that I can tell. But I dont drop it for the milage, I drop it so I can see a car behind be.

 

I don't see the gears hurting milage as long as you're not trying to go 80mph up all these hills, higher gears would just make it worse by forcing the computer into open loop more often. The problem is aerodynamics and that starts at the big square front bumper on these trucks which you can't do much about. BTW.. what are you getting for milage anyway?