Today my truck history report arrived from Ford:

1978 Ford F-250 4x2 Model
351 CID, V8 Gas Engine
Manufactured in our Mahwah, New Jersey Plant

This vehicle was produced on 05/03/1978
* Nectarine Dark Metallic Exterior Paint (Paint Code 2931)
* Style Side Pick-up
* Chamois Colored Cloth and Vinyl Trim Scheme
* Orange and Chamois Tape Stripe
* Ammeter and Oil Pressure Gauges
* Warner 4-Speed Maual Transmission
* 3.31 Rear Axle Ratio
* Power Steering
* 750 x 16" KYB Tires
* Spare Tire
* Locakable Hood Release
* Front/Rear Single Shocks
* District Sales Office: New York
* 133" Wheelbase

What is the gear ratio? What does that mean. I'm not knowledgeable on that.

In your rear axle, the differential can be 'geared' differently from truck to truck.

The back running gear can be low ~3 will give you low RPM's on the highway and (in theory) improve fuel mileage. This can increase top speed but make it accelerate a little slower.

If you get a higher rear ratio ~4 you can acclerate much quicker, but you'll sacrifice top speed along with turning much higher RPM's on the highway and in theory decreasing fuel mileage.

Gears are also important when you're choosing your tire size. If you increase your tire size, it helps to have a much higher ratio to return the truck to it's original overall drivetrain ratio.

I'm no expert and someone will probably come along and it explain it better, but that gear in the rear differential is your 'gear ratio'

Ryan

3.31:1 means the drive shaft (pinion shaft) turns 3.31 times for every one revolution of the ring gear in the differential.

I don't ever recall this ratio being used.


The higher the number ratio the higher the rpm of the engine and are usually installed on 4x4's where low end torque to turn the wheels is required. Also in drag racing where power to the wheels is needed for better starts.

The term "Highway Gears" refer to the ratio of 2.75,2.79,3.00

I guess my truck is unique if you never hear it being used.

Doesn't axle code 23 in the chart show a 3:31 axle ratio? It is an F-250.

That it does.

correct, i forgot about the dana 61

78F250 said:

Today my truck history report arrived from Ford

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That's nice. However it you want addidtional info, FoMoCo doesn't have anything available.

In fact, the info you got from FoMoCo actually came from elsewhere.

In the late 1980's, Ford was gonna throw all this info into the TRASH!

A Mustang nut from Phoenix AZ heard about this...and got ALL of it.

So...when Ford needs this info...they have to get it from Kevin Marti better known as martiauto.com.

I've never messed with truck histories so I've never heard that bit of info - thanks Bill!

Hey look who is awake and posting in California

Mil1ion said:

correct, i forgot about the dana 61

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Yup. 3.31 or 3.07. My truck has the 3.07...

BKW said:

That's nice. However it you want addidtional info, FoMoCo doesn't have anything available.

In fact, the info you got from FoMoCo actually came from elsewhere.

In the late 1980's, Ford was gonna throw all this info into the TRASH!

A Mustang nut from Phoenix AZ heard about this...and got ALL of it.

So...when Ford needs this info...they have to get it from Kevin Marti better known as martiauto.com.

Click to expand...

holy crap are you serious? they were gonna throw it away? WTF!!!!!

IIRC Bill stated that on a previous Build Sheet Thread.....thanks again Bill for the info and the Site name.

flareside_thunder said:

IIRC Bill stated that on a previous Build Sheet Thread.....thanks again Bill for the info and the Site name.

Click to expand...

well dang i never read it i guess. mucho gracias to bill for that info.

If anyone wants the E-mail for the build sheet it is [email protected] ...you need to include your First and Last name, your mailing address, Build Sheet as the subject line and of course, your VIN number(s)

nflfreak43 said:

holy crap are you serious? they were gonna throw it away? WTF!!!!!

Click to expand...

Absolutely serious.

I also knew what Ford's plans were, but I hadn't the time to take off from work...and head to Dearborn with several semi's to load it all up...

Nor the space to store all this jazz, so I did nothing.

Now...If I had known Dennis back then....we mighta/coulda got it.

And....then we would be Mil1ionaires like 'ol Marti...from selling all this jazz to car/truck collectors and historians.

Luckily if you order it through FoMoCo it's FREE.....