I have an original 66 F-250 4x4. i have 35's under it for now and was wondering if anyone knows who can make gear drive to adjust the speedometer. its hard to explain but i was told that i can get a gear drive adapter that the cable to goes into one side and the other side goes to the t-case to correct the difference in speed because of the tire height difference.

You should be able to get the drive and/or driven gear from Dennis Carpenter to correct your speedo:

http://dennis-carpenter.com/

UTfball68 said:

You should be able to get the drive and/or driven gear from Dennis Carpenter to correct your speedo:

http://dennis-carpenter.com/

Click to expand...

The plastic DRIVEN gears are the same from 1960 thru today, so they are still available from Ford.

But does this truck have a plastic driven gear? No...it does not, it's iron.

There are five different tooth counts, all are obsolete, DC has none.

Some of the DRIVE gears are steel, some are plastic, it depends of the trans type. There are three different tooth counts each. All are obsolete, DC has none of the steel gears.

I've looked these gears up dozens of times for ppl. There are about 50 total of the five different tooth count iron driven gears available at a few Ford dealers, obsolete parts vendors.

About 15 total of the three different steel drive gears, about 20 of the plastic types.