1961 - 1966 F-100 & Larger F-Series Trucks Discuss the Slick Sixties Ford Truck

Rear End Ratio

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Old 02-09-2011, 09:48 PM
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Rear End Ratio

Help guys..................I drive a 1964 F100 everyday to and from work. Round trip is about 88 miles a day. I am running a 351 windsor mated to a mechanical AOD. Traveling at 60 mph im running at 2500 rpms. Since all my driving is interstate this tends to drink a lot of gas. Im running on 15 inch rims. Does anyone else drive their truck regularly and have any suggestions for a better gear ratio to lower my rpms and try to save some money on gas? I burn about 13 gallons of fuel every 2 days. I dont feel its worth it nor can i afford buying a new truck. One of oue salesman have a new 2011 F150 and only gets 18 miles per gallon. So a new truck is not the answer. Besides mine is paid for (hahahaha). I have thought about larger wheels but dont want to take away from the originality appearance of the truck but not agianst it. Any suggestions or information y'all can give would be greatly appreciated.
 
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Old 02-09-2011, 09:54 PM
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I run 3.73 gearing (F250 Dana 60) and am a tad below 2000rpm at 60...I'm guessing that would help a bit with mileage, but the aerodynamics of our rigs are not exactly helping...are you timed well and have good carb settings...that can help a touch.
 
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Old 02-09-2011, 09:55 PM
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I am guessing you have 3.89's or 4.11's. I would imagine something in the 3.25 to 3.50 range would be a big improvement.

Jim
 
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Old 02-09-2011, 10:03 PM
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Originally Posted by Voodoo66
I am running a 351 windsor mated to a mechanical AOD.
Well you're already in better shape than a bunch of us in that you have overdrive. If it is for sure shifting into overdrive then you need to figure out what gears you have now, if ya got 4.11 then I'd go to 3.70. If ya have 3.89 or 3.70 then I'd try 3.50s. These are common numbers for 9inch, not sure if that's what you have....
 
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Old 02-09-2011, 10:33 PM
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I could be wrong BUT i thought i decoded the door tag to say it was 3.73's. Is 3.01's to low for a truck like ours? I dont wanna loose the functionality of the truck if i do need to pull something and I dont have my '65 F250. Im not looking to win races running from red light to red light but want it to be a comfortable crusier, especially once I add A/C. I just worry about the 3.01's being to low of a gear.
 
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Old 02-09-2011, 11:03 PM
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I tend to think 3.01's would be to tall. That would be more appropriate for a car equipped with smaller tires. A truck, with OD and tall tires would likely struggle.

Jim
 
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Old 02-09-2011, 11:19 PM
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So I guess we're not talking about a 9" rear axle or do you know?
What size rear tires do ya run?
 
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Old 02-09-2011, 11:41 PM
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3.25's seem to be a good all around ratio and they're a dime a dozen at pick & pull.
 
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Old 02-10-2011, 02:08 AM
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Until you find out what your ratio is right now for sure this is all a guess, so start there.

Easiest way to know for sure is to do a little counting. Jack one rear tire off the ground and mark a spot on the inside edge that lines up with something, likely the spring, and a mark on the driveline that lines up with something. Next turn the tire 2 full turns while counting how many times the driveline turns. How many times it turns is your gear ratio. Parts of turns can be hard to estimate if u want to be percise do it the same way but turn the tire 20 times and devide the number of driveline turns by 10.
 
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Old 02-10-2011, 05:28 AM
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Voodoo, I luv my ol truck, but it aint no way that I would drive it 88 miles a day unless it was related to the job. You need a little hiway cruiser that will get you 25+ mpgs, and save the wear & tear on your truck. Our trucks are like brick bats on the road with no aero at all. You would come out ahead at the end of the year.

You need to get after the math, and make sure you have the correct speedo gear for the setup that you currently have. I run 3.00 rears behind a FE C6, the truck has plenty of power on 15in tires. 2050 @ 55 mph, 3000 is about 82 mph.

The W doesn't have the gonads of the FE so I would not have a final below 3.00 in OD. I have run 2.75 gears, in the truck, it will cursed fine but take off was was wimpy. I would not be afraid to go 2.75 in OD with the FE.

Keep it tuned, are you running electronic spark?




John
 
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Old 02-10-2011, 06:30 AM
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Well my old truck is my only option at this point time. I am running a MSD pro billet distributor, with 6A, and blaster 3 coil, and E3 spark plugs. As far as the rear end goes it is a 9". I know my front tires are small but my rears are P275/6R15.
 
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Old 02-10-2011, 11:56 AM
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Likewise I have a 9" rear. The 9 has ratios all over the place to get the best performance the ratio needs to match the need. If you were to put a 3.00 ratio with the OD it wouldn't run in OD. A 4.11 or higher and your engine is turning to many rpms.

I suspect a 3.50 or 3.75 would be a good ratio to use with the AOD.



John
 
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Old 02-13-2011, 05:26 PM
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Originally Posted by Voodoo66
One of oue salesman have a new 2011 F150 and only gets 18 miles per gallon. So a new truck is not the answer.
18 MPG? That's the EPA rating. Your actual MPG will vary. I doubt anyone will get 18 MPG...unless they drive 55 with the A/C off.

Onboard computer sez: Best so far for my 2011 F150: 12.9 MPG!!! / If you want good MPG, buy an econobox.
 
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Old 02-13-2011, 07:52 PM
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Originally Posted by NumberDummy
Onboard computer sez: Best so far for my 2011 F150: 12.9 MPG!!!
Bill, you like yours so far? Tell us a little about it (besides what's in your sig.) if ya don't mind.
 
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Old 02-14-2011, 02:36 AM
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Originally Posted by RJP66F100
Bill, you like yours so far? Tell us a little about it (besides what's in your sig.) if ya don't mind.
Has every available option...except 4WD, Navigation, DVD...and a bedliner.

MSRP was $39,900.00. One would think for this price, a bedliner would be included.

It's 8 1/2" shorter than 20' so it barely fits in the garage...and this is the short bed.

As soon as I get around to taking some, will post some pics of this elephantine behemouth (which is huge compared to the 2008 Fusion I traded in).
 


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