You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!
I'm pretty new to all of this so your help would be much appreciated. Does anyone know what the standard gear ratio would be on a 1968 F100 Ranger/390/Automatic? Or is the an easy way for me to find that out. Thanks.
68, You can go under the truck and look around the bolts in the center section for a tag that has numbers stamped in it. I find this site to have useful info to insite of the Ford rears, you may like it. Kevinstang's Ford Nine Inch Differential Page +
Ford built many trucks like yours came with ratios in the 3.00 range.
John
__________________
In the cool still quiet hours of night, you can hear chevies rusting away.
I'm pretty new to all of this so your help would be much appreciated. Does anyone know what the standard gear ratio would be on a 1968 F100 Ranger/390/Automatic? Or is the an easy way for me to find that out. Thanks.
The rear axle ID tag is under one of the bolts that attaches the carrier (pumpkin) to the housing, usually at 5 o'clock.
Do not be surprised if it's missing.
The AXLE code is listed on the Warranty Plate, which is located on the left door face below the latch.
There are at least 7 different AXLE codes, here's a few examples:
07 = 3.00-1 // 08 = 3.50-1 // 17 = 3.25-1.
__________________
Bill // Retired Ford Parts Manager // SoCal Chapter member // Part Number Research: 1928/2001 FoMoCo vehicles.
Related question:
I have a 69 360 with 3 on the tree, and a 3.25 rear end. If I want a little more low end but still want to be able to cruise comfortably at 60-65 on the freeway, what is the highest numerical gear I should go with (assuming H78-15 tires). Right now I can hear the tires more than the engine at 65, so without having a tach to reference, it seems like I can step up a few numerical gears.
H78's? How old are those tires? If they are 30" in diameter you should be turning 2366 rpm at 65. If 29 you turn 2448.
Change your axle to 3.50, and you will turn 2548 with 30s, 2635 with 29s.
3.70s: 2694 or 2786.
Not sure the change will be worth it.
Are you in love with your 3 speed and column shifter?
A change to a NP435 or T18 would retain your current cruise rpm, and give you that granny low for the heavy take off situations. Not sure of all the ratios involved, but they might even be better 3 to 4 than the 3 speed is 2 to 3.
To calculate more variables, or if your tires are different than 29 or 30, different speeds etc:
H78's? How old are those tires? If they are 30" in diameter you should be turning 2366 rpm at 65. If 29 you turn 2448.
Change your axle to 3.50, and you will turn 2548 with 30s, 2635 with 29s.
3.70s: 2694 or 2786.
Not sure the change will be worth it.
Are you in love with your 3 speed and column shifter?
A change to a NP435 or T18 would retain your current cruise rpm, and give you that granny low for the heavy take off situations. Not sure of all the ratios involved, but they might even be better 3 to 4 than the 3 speed is 2 to 3.
To calculate more variables, or if your tires are different than 29 or 30, different speeds etc:
Sorry for the thread jack... but yeah, the tires are OLD. I just got the truck and it had been sitting for a long time. I plan to replace the tires with the modern equiv soon. I'm not in love with the three on the tree, but then again I'd rather just leave it as is if possible. I don't want to cut a hole in the floor, and don't want an auto.. 3.70 sounds pretty decent, although I'm not sure if it would make first gear too short. What's the redline on these motors anyway?
3.70s would allow you to run a little taller tire... gonna be a bit short with 29 inch tires.
Redline on a '69 360? When new they produced peak hp at 4400 rpm. You'll not get much higher than that, and would be well advised to stay below 4000 with an old motor like that, perhaps even 3500....
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.
