Fun with the 9 inch...

my66longbed · Post by **my66longbed** » August 30, 2006, 11:36 pm

So this is my first time taking apart a ford 9 inch, and I am having a bear of a time. I have a few questions.

1. When I got my slick the previous owner at some point had the diff apart and had lost the rear axle tag. The ring is 35 teeth, and the pinion was 10, so that would give me a 3.5 ratio. Correct? Just double checking my math..

I am having a hard time figuring out what gear ratio I should have. By this I mean with figuring in the engine <428 Stroker>, transmission <NV4500 5 speed>, and such what gear ratio would be best for my setup. What other factors should I be figuring in?

2. I would like to make my 9 inch a posi. Does anyone have any suggestions on kits to convert over to a posi setup. I was looking at:

http://www.4wheelerssupply.com/catalog/ ... 262469fedc

But I don't know if this would be the best option. Has anyone done something like this, or have a better suggestion?

3. I would like to convert the this from drum brakes to disc. I already have converted the front end, and every 9 inch I have ever seen has drum brakes.

I appreciate your help. This is my first restore and I am learning as I go...

Thanks!

Comet · Post by **Comet** » August 31, 2006, 12:26 am

Well, I'll try to answer some questions.
You have the ratio figured out right.
The lock right is an affordable kit that should be fine for most applications and is an easy install.
As for what ratio you should run depends on lots of things. How you drive it, do you want mileage or hard launch capability or grunt to pull stumps? How big are your tires, etc.
Discs in the rear are a waste of money IMO. There is little weight back there and the difference is negliable in braking as something like 80% of your stopping force comes from the fronts. Currie Enterprises probably sells disc kits if you must go that route. Even today's hot rod F150s, etc use disc/drum set ups.

my66longbed · Post by **my66longbed** » August 31, 2006, 10:42 am

Yeah I have been going back and forth over if the 3.5 is going to be fine or if I should switch it out. My slick is 2wd, and I don't plan on using it as a work truck. So mainly the weekend driver. So far the engine is going to be around 550 horse <at the crank> with ton of torque. Don't plan on racing it, but from time to time putting the hondas back in their place. Still don't know what I am going to do from tires and rims...

For me. I just hate drum brakes. Would rather have disc for my comfort level. I pulled the front disc brakes from a 74 f100 not to long ago, and just need to something for the rear.

My slick is torn down to the frame rails right now and I am doing a complete restore. I am focusing right now on the drive line...

Garbz · Post by **Garbz** » August 31, 2006, 10:50 am

Rear discs are problematic with the 5 on 5.5 pattern... everyone and thier brother makes 5 on 4.5 and 5 on 4.75.. even 5 on5 but no 5 on 5.5 rotor hats.

Easiest method is to use longer wheel studs aand discs from a 70s or 80s F150 machine the cneter to clear the axle and some custom brackets from Speedway. Need to use a GM mid seventies intermediate caliper. or a later one with integral E brake.

There a 2 pin slider type.

I have also heard that a subaru samauri rotor will work and is thinner in the hub area.? unconfirmed but they were 5 on 5.5 pattern.

But with the extra space from the disc sandwitched custom back set rims may be needed.

Garbz.

my66longbed · Post by **my66longbed** » August 31, 2006, 12:05 pm

Just also wanted to say that I am very happy I was introduced to this group. There is just such a wealth of knowledge between everyone, and politics seem to be at a minimum. Hopefully overtime I would like to attend slick stock and some of the other gatherings.

castruck_1964 · Post by **castruck_1964** » August 31, 2006, 3:21 pm

two things
1) is the lock rite a clutch or ratchet type locker reason being is ratchet type. AKA; detriot lockers tend to be a little noisy going around corners.
2) As for the gear thing you need to know how tall your tires are going to be and what the ratio is the transmission in fifth gear or figure it out at 1 to 1 . And lastly what RPM you want to turn the motor at what given cruising speed :?:

All these factors go into figuiring out rear end gear ratio :!:

hope that helps a little :?:

Comet · Post by **Comet** » August 31, 2006, 4:51 pm

For discs...
http://www.currieenterprises.com/cestor ... px?id=1008

Paul Merrell · Post by **Paul Merrell** » August 31, 2006, 7:39 pm

You could use a 80-84 maybe later not to sure on the years but Ford put a 9inch in the granada that has dics brakes and a locker in it. I don't know what the wheel to wheel measurement is but it could work as parts for yours the tag has a L for locker

64 f100 · Post by **64 f100** » September 1, 2006, 7:33 am

Your stock rearend has 28 spline axles, which may not take the torque of your big block. You may want to consider going to a 31 spline axle, which is another headache. The 31 spline axles, have the brake drum set out further, from the backing plate to accommodate the wider brake shoes. The difference is about 1/4 to 1/2 inch.. You then have to use the drums and backing plates shoes etc, that match the axles. In addition, these axles don't slide into the internal splines of the traction lock assembly far enough, on the driver side, in my opinion. You would need to have some longer axles either shortened, or custom made. Your rearend ratio sounds close to right, to me, for your everyday combination use. With the 428, your not looking for gas mileage, but we all feel the bite at the pump.

Rich

F-100XL · Post by **F-100XL** » September 1, 2006, 9:06 am

my66longbed;
As to the 28 spline axles,my suggustion would be to call either Strange Engineering or Moser Engineering and tell them that you need a pair of axles. I have run Strange Axles(28 Spline)since 1964 in the XL and had very good service from them. They are twisted one spline right now and I don`t worry about them ,one bit. Either of the above companies can fix you up on any rear problems or questions that you may have. Good luck with your thuck.

Bill.

Jarrod · Post by **Jarrod** » September 1, 2006, 6:24 pm

Your trans is has a 5th gear over drive. Your 3.50:1 ration would be a good option in my opinion since the 5th gear is like .75:1. If it were me I would go with like a 3.73:1 and get a better launch and still have great cruising rpm in 5th gear. I think that diff that you are wanting might be a little light weight for 550 horse and at least that much torque. IMO a detroit true trac posi would be a better. Sounds like an awsome ride. Have Pics? :lol:

Jarrod

rob66f100 · Post by **rob66f100** » September 2, 2006, 12:53 am

i had a 77 ltd wagon 9 inch trac loc and disc breakes

64 f100 · Post by **64 f100** » September 11, 2006, 8:56 am

I bought a Nascar locker for my Red 64, which I built in a war case with some good 350 gears and new bearings. I needed a rearend for my green 64, as it went out, so I stuck it in that truck, for a couple thousand miles. It really didn't work out well with the granny four speed. It's a 31 spline, and I would sell it, or remove the locker and sell it, as I need the 3.50 gears, and wouldn't mind keeping the war case ( extra ribbing like the N cases). If you are interested, you can e-mail me. rdkearney@yahoo.com

Rich

61ford · Post by **61ford** » September 13, 2006, 5:19 pm

on the disc brakes im wanting to do the same thing,they sell kits that they call explorer disc brake kits can you not go to the junkyard and just buy the brakes off of a late model explorer rearend for a 9 inch?im just wondering bc ive never heard anyone bring up this point they usually say swap the whole rear?anyone know the answer to that?if that doesnt work you can swap in a 8.8 and i think theres little mods to be done to that

64 f100 · Post by **64 f100** » September 13, 2006, 7:20 pm

Anything you do, is going to be costly, and time consuming. First, it isn't neccesary to have disc brakes on the rear, because most of your braking comes from the front. When you hit the brakes your weight shifts to the front. Second, If you go with 31 spline axles, and third member, you have to go to the wider brake drums and shoes. This will increase the effectiveness of your rear brakes. Third, there is a disc brake rotor for the 2002 Dodge pickups, that may work on our trucks. Haven't checked it out yet. This still leaves two problems if it fits. The emergency brake issue will have to be addresses. In the aftermarket produced brackets sold on Ebay, they reccomend 85 Buick calipers as these have integral emergency brakes, with the caliper . Now whether the brackets and calipers will work with the doge brake rotor I don't know.

Changing the whole rearend, means another set of problems. Width, axle bolt pattern, perches, etc.

Rich

Paul Merrell · Post by **Paul Merrell** » September 17, 2006, 9:10 pm

I checked the rear end I got from a granda that has disc brakes and is a 9 inch from axle to axle is 58 1/4 that is where the wheels bolt up I can check the bolt pattern if needed. It also has a locker from the factory

Hawkrod · Post by **Hawkrod** » September 17, 2006, 9:36 pm

Some FYI: The Granada rear is good for a Mustang but not really good for a pickup. They have 28 spline axles and are very narrow. They also have a 5 on 4.5 bolt pattern which is much smaller than our trucks 5 on 5.5 pattern. Also, the L stands for limited slip not locker and no Granda's ever came with a locker (actually lockers were only offered by Ford in 1970 and 1971 and only as an option on cars with 4.30 gears). The mid 70's fullsize cars also had a disc brake option and those are 5 on 5 bolt patterns so they still are not an easy swap for our trucks. The Ford Explorer never came with a 9 inch rear, it has an 8.8 which is a totally different design (looks similar to a dana 44). The Explorer kit is 5 on 4.5 bolt pattern and does not fit our trucks and actually only fits certain 9 inch housings. Hope this helps, Hawkrod

Paul Merrell · Post by **Paul Merrell** » September 17, 2006, 9:51 pm

thanks Hawkrod I know its narrow but I did know for these trucks My truck has a dana 60 And I thought the bolt pattern was differant

my66longbed · Post by **my66longbed** » September 19, 2006, 2:40 am

Thanks all for the feedback. Sorry I have been unresponsive. I got pretty sick this last week... Just now getting back in the swing of things.