My history teacher's brother-in-law has a good used set of 3.50s for a ford 9. My question is if I can easily put them into a 64 f100 rear end for my 51. How hard is it to change out the ring and pinion? He wants 50 bucks for the gears. Is this reasonable?

 

Sure, as long as your truck has a 9 inch in it now.
The gears have to be adjusted after they are install so you will need a shop manual.
Try this site too;

Kevinstang's Ford Nine Inch Differential Page +

 

Thanks for the link. So on the 9s do you have to use shims to set the backlash?

 

A good investment for me was to purchase Part # 16-1600 CD from TechnicalVideos.com

It fully covers the 9", GM, Dana etc. The video is very well made and easy to see what's going on. The best part is if you miss something or it doesn't make sense, you can back it up and play it as often as you need to.

Dawgie

 

From a weak an unreliable memory I think it is shims / crush sleeve on the pinion and big adjusting nuts on the crown gear backlash.

 

You can buy complete 9" center sections with the 3.50 ratio for dirt cheap at U-pull's, just check your spline counts.

 

it's not difficult to do but takes some patientence and proper tools to do the job correctly.

you will need
- good dial indicator with mag base
- inch pound torque wrench to set the proper crush on the pinion
- set of shims (can be bought at local Ford dealer or most speed shops or driveline shops) to set the correct backlash
- spanner to set the proper preload/ backlash on bearings in the pumpkin (easy tool to make at home, no need to buy one)
- good marking compound to set proper tooth pattern. the tooth pattern is probably the most critical setting you have to get right so the gears last and don't howl. this is the part that takes the most patience to get correct as it is a combination of proper backlash and bearing preload.

lots of good sites on the web to look at as the 9" is a very popular rear end not only used by the Ford guys but a lot of the other car guys also.

it is not a tough thing to do but does take a little patience and reading to do it correctly. i would also change the bearings out if replacing the gears. cheap insurance and you can buy the complete bearing kits with the marking compund for around $100 from most shops or off ebay. just make sure they are offering quality bearings and match your bearings as Ford used 3 different type of bearings in these rearends depending on application.

rgds
Mike

 

some other planet from where I live maybe..

Sam