That's not that bad

 

I have the I6 with 31'' tires and 4.11 gear ratio. You can't go wrong with 4.10's if you don't care about mileage. I can cruise at 70+ mph and never come out of OD on the hills.

A 4.11 gear ratio with OE sized tires is just plain fun if you ever wanted off the line power. I cruise at 2,200 rpm or so at 60 mph and 2,500 or so at 70 mph+ . I can pull a house down too if I ever wanted.

The 3.08 gear I had wasn't bad either. I could cruse at 80 all day and get nearly 17 mpg.

 

If you want to know what the MPG and top speed would be with different rear differential gears-all you have to do is:

Drive around in fourth gear for what 3.55 would be like

Or

Drive around in third gear to find out what 4.10s would be like (with your present five speed manual and 2.75 gears).

I havent done the exact math-but if you have a manual transmission-it is easy to determine what different lower final drive gear ratios would be like in a vehicle. Just drop down one or more gears and drive in them and pretend that you are in top gear. Check your MPG in that lower gear and top speed.

I bet that doing this will make you like your 2.75 all that much more. You dont need low speed torque multiplication with the 4.9.
This wouldnt be exact-but would give you some sense of what different axle gear ratios would be like-when in top gear. And wouldnt cost you any labor or parts expense to find out if you would like the different overall gearing.

You also have a special low speed torque camshaft from the factory-because of your 2.75 gears. This 4.9 is a Factory Special and already increases the low speed torque of this engine. Even more torque than standard 4.9 engines. The 2.75/special cam 4.9 was a MPG package from the factory. This combination got the best EPA MPG of all F150s.

You dont need granny gears in the rear differential-Henry has already thought of this at the factory with the special cam.

Be glad that you have this special MPG factory package. I have a 302/4.10 and I have to make due with just 20.8 MPG. Ouch!

 

OK.. I don't want to call BS on you but I have never heard of this.

 

yowzers!! your getting 20mpg with a 302 and 4.10 gears?!?! you must be one of the lucky ones. i see you have a 5 speed though which probably helps alot.

 

My 1992 F150 FSM states this. No BS involved. 2.75 factory ratios were installed on 4.9 that have a different cam profile from the factory. Ford used the 2.75 and this special cam to get 19MPG highway-to fight the imports. And to increase their CAFE ratings.

If you dont believe that there is a special cam for the 4.9-call your Ford dealer parts department guy and ask for a 4.9 cam-and his first question will be: Does it have a 2.75 final drive ratio rear axle??

The special cam 4.9 is rated 145HP and 265TQ SAE NET

The normal cam 4.9 is rated 150HP and 260TQ SAE NET.

 

The 4.10s dont necessarily hurt MPG if you keep the vehicle speed down. I travel around 60MPH or less and drive like the old man that I am. The 4.10s are sure easier on clutches-very little slipping is necessary from a dead stop-even with load.

I also keep my RPM on the highway around 1900-2100 RPM-that seems to be a sweet spot for my 302.

I have also found out that my KS( Knock Sensor) equipped 302 likes higher octane gasoline. The MPG increases with the higher octane. It has 110k miles and I suspect that there is some carbon build up on the pistons and that the static compression has increased some since new. And higher octane allows more ignition advance with the KS- and more MPG.

The 4.9 also is knock sensor equipped from the factory.

It is always easy to beat EPA ratings with a vehicle has a manual transmission. This 302 F150 of mine has a rating of 17MPG HWY per the EPA. I am not beating their rating by much! I was even able to beat the EPA ratings on my Honda cars years ago--because they had manual transmissions.

 

good info, ive always wanted a 302 with a 5 speed, having only driven a 300 6 with the 5 speed. theres one nearby for 500 bucks i might snag up. i dont drive fast in a truck on the highway typically i cruise about 70mph anything above 80mph and the mpgs start to drop like a rock.

 

If you buy a 302 F150-check the rear axle ratio code on the VIN sticker near the drivers side striker plate in the door frame. The 4.10 limited slip will have code H5. The 4.10 will also include TracLoc-limited slip differential in most cases

If the 4.10 was good enough for the first generation Lightnings-it is good enough for our trucks-right??

 

Hey... I don't know everything.. just wanted to see what you had to back this up. There is an awfull pile of nonsense floating around these forums sometimes it's hard to sort the chaff from the wheat. However I still think Ford got it all wrong with these high gear ratios, your 302 truck is proof that better than average milage is possible with lower ratios when the vehicle has an OD tranny, and it doesn't kill the trucks hauling capacity like 2.73s or 3.08s does. I have seen lots of I6 trucks with 3.55 gears getting better than 20mpg too.

 

Paul:

Sorry-I didnt mean to sound defensive. You are one of the most knowledgeable and agreeable posters on this site.

I always thought it strange that Ford would go thur the expense of equipping some of these 4.9s with different cams. The torque curve cant be changed that much to warrant the added expense. CAFE ratings were the reason.

I suspect that steady highway speed will net very good MPGs with these 2.75 4.9 equipped trucks. Ford does state that they shouldnt pull any size trailer though. It also most be real "quiet" in the cab when driving 70 MPH-with the engine speed being so low. I would like to own one and see what MPG I could get out of it.

I am getting 23MPG HWY with my 4.0 straight six ,3.55,manual 5 speed, Grand Cherokee.And have gotten 31MPG HWY with 2001 4.6 ,5sp manual 3.27 Mustang.

 

Yeah it does seem kinda crazy for 5 ft/lbs extra.. I mean how much difference would that really make, I bet you couldn't even feel it if you drove two identical trucks with both cams back to back. 50 ft/lbs would be noticable and worth the effort IMO.

It'll get good milage on flat roads but that's it, if you have any hills there goes the milage. I grew up driving these Detroit turds and it's my experience in real world conditions that more gearing delivers better milage.. up to a point. Obviously if you rev the motor too much milage suffers too, but a little more gearing takes the load off the motor and with the right combination of gearing and motor these trucks can do quite well.. loaded and empty.

And that's the big issue I have with this, what the hell is the point of a pickup that can't tow/haul anything, if it were a minivan or even a sport utility I could understand, but a pickup?