i have a 1975 f250 camper special with a 460/c6 trans, and when i bought it the guy told me that because the rear tires are so bigger than the stock tires that when im going 40mph im really going 30, and when i go 60 im really going 50...and so on. is there a way to change that so my mph is my acutual mph?

 

http://www.transmissioncenter.net/sp...___va.htm#ford

http://www.tciauto.com/tech_info/speedo_gears.htm

 

You need to change the speedometer gear, and the best way to do that, would be to go to broncograveyard.com
They have a calculation that can tell you which gear you need, and they sell all different kinds for a few bucks.

Or you could always change the gears in your axle, and then the truck would have better accleration, get better gas mileage, and correct the speedo.

 

With a 460 he has plenty of torque to handle the larger tires. The larger tires will help his mileage. His best and cheapest route is to get a speedo gear.

 

well, what size tires do you have?
For all I know you have 44s and theres no way that 460 would like those to much with about 3.50 gearing.
That's all I was saying.

 

I posted the the exact same thing you mentioned one post above yours.

A speedo gear calculator

 

Sorry Mil1ion, I fiqured you posted a link to a calculator, but I was just saying the one I knew too.

 

im not sure exactly its a pretty new truck for me, when i get home i'll measure. do i measure the outside diameter of my rim, or bottom of tire to top? also when i bought the truck the guy said it was pieced from 5 different trucks. whats the like ability of the gears ratio on my door to be the same in the axle?

 

i would quess my tires are about 32 inchs in back top to bottom, and about 28 inch in front, but i will douple check to make sure

 

Speedometer correction formula:

# of drive teeth(in tranny) x axle ratio x (tire revolutions per mile) / 1000= # of driven teeth on the speedo cable end.

 

Are the tires sizes metric? 285/75R15 or somthing like that, b/c if it is that size in the rear then they are 32" tall and 11" wide.
If the tire size is only about 32"tall, then your cheapest and best suited fix would be a new speedo gear.
BUT if you have the money, switching gears to about 3.73 would help acceleration and mileage a little bit.

 

how do i find what gears i have? im not sure if there metric tires,but i do know that they are wild country brand though

 

There is a number or letter on the driverside door jam that Mil1ion can help you out with if you need, or they have a metal tag on the rear bolt circle with numbers and letters on it, and if you get back to us on here with either of those we can let you know what gears came stock in the truck.

 

Gear a 460 as low numerically as you can for mileage. Some of the 460's with a 9" in cars that were heavier than these trucks were around 2.5:1 for mileage. You do NOT want to turn more RPM's with a 460 or they will suck gas bad!

 

the guy that I bought my truck from said when he put in the 460 and c-6 trans, that it was geared really low and I could pull a stump out of the ground, and the other day I was driving and wasn't paying attention and I was driving 60 mph in 2nd gear? Is that GOOD or BAD?