Ford 9''?

**Dave-TransAm** · 07-10-2011, 10:31 AM

While my car is down I was thinking about throwing a 9" rear end in it but im not sure if a Ford 9" will fit. The junkyard by me has quite a few Police Interceptors with one in it that I can get very cheap. Just wanted to see if it would fit in my LT1 before i actually go buy it. Thanks for the help

**5.0THIS** · 07-10-2011, 11:18 AM

All of the big F-body axle manufacturers sell bolt-in Ford 9 inch axles, along with GM 12 bolts and Dana 60s. My personal recommendation would be the dana 60 (I believe Strange does the Dana 60). The dana 60 will be the strongest axle even over the 9 inch, and it has alot less parasitic loss than either the 9 inch or the 12 bolt. The only negative is it is the heaviest axle, but I believe it is worth it with the extra strength and not losing as much power through it.

If you try to buy a 9 inch out of an old crown vic or whatever, it will be a headache to get it to fit. It will likely be the wrong width, and all of the mounts will have to be ground off and new mounts added for trailing arms, panhard bar, brakes, and you would need a new pumpkin for the torque arm to mount on. Also, the bolt pattern might be different, I dont remember the Ford's bolt spacing right off hand, so maybe new wheels. And keep in mind, putting on all of these new mounts for suspension and brakes is a precision operation. That stuff needs to be spot on or the alignment of the axle in the car would be all screwed up.

**Dave-TransAm** · 07-10-2011, 11:23 AM

how much would a Dana 60 cost? Or a 12 bolt? And how much power can a 10 bolt usually hold? Im looking to get it up to only about 400 horses.

**5.0THIS** · 07-10-2011, 03:52 PM

Looks like 2350. All I had to do was go to their site and look it up. Go there if you want details

You can break a 10 bolt with stock power levels. It isnt power that necessarily kills them. It's when you try to hook all of that power with sticky tires such as drag radials or slicks. People have broken them on street tires though, so it does happen, although it does help having an auto tranny, as the rear end gets shocked alot less when the car is launched.

**Wesman** · 07-11-2011, 04:34 PM

Originally Posted by Dave-TransAm

While my car is down I was thinking about throwing a 9" rear end in it but im not sure if a Ford 9" will fit. The junkyard by me has quite a few Police Interceptors with one in it that I can get very cheap. Just wanted to see if it would fit in my LT1 before i actually go buy it. Thanks for the help

Won't work. As 5.0THIS said, the rear would need to have all of the mounts fabbed up, the most difficult being the torque arm mount.

**con_fuse9** · 12-02-2011, 03:14 PM

Originally Posted by 5.0THIS

All of the big F-body axle manufacturers sell bolt-in Ford 9 inch axles, along with GM 12 bolts and Dana 60s. My personal recommendation would be the dana 60 (I believe Strange does the Dana 60). The dana 60 will be the strongest axle even over the 9 inch, and it has alot less parasitic loss than either the 9 inch or the 12 bolt. The only negative is it is the heaviest axle, but I believe it is worth it with the extra strength and not losing as much power through it.

It all depends what kind of job you expect the axle to do. The 12 bolt is reasonably strong design that is probably good enough for the average person. If, however, you are drag racing with slicks and a full weight car, you need to watch things like the spider gears etc. A known weak link in the 12 bolts (Moroso makes some interesting replacements).

The Dana 60 is a 3/4 ton truck axle. 9.75" ring gear makes the load carry capability very high. Came stock in some Chrysler Hemi and 440 power muscle cars. Under drag racing conditions, the weak link is the pinion. I have seen them snap on heavy, high torque cars.

My personal favorite is the 9". The housing is completly weldable (its steel not cast iron) so the housing is easily modified to fit just about anything (including F-bodies). The housing is capable of handling pro-stock level horsepower and 200mph runs down the 1/4. The big advantage is that the pinion is supported on both ends. Simple rule of thumb, support something on both sides (double shear) vs. one side (single shear) and you get 4x the strength. Now in the case of the 9" the actual pinon is a little thinner so you aren't getting the full 4x, but the ability to handle the shock load is legendary. Consider this, under high torque situations, metal bends, by supporting the pinion on both ends the pinion doesn't deflect away from the ring gear and you keep the ring gear wear down. The bad news? Well, because of the extra support, the ring gear had to be moved down a bit in the housing. As a result, the extra angle reduces the efficiency. Not a lot, and it depends on how much torque you are putting to the axles, but in theory its more. Keep in mind that at some point pinion deflection and distortions in the housing will do more damage on the other designs. The 9" is also by far the easiest to setup. The Dana 60 is the worst.

With the Dana 60, shims are placed under the bearings so to change any shim, you must have a bearing splitter and press to get them on and off. Royal PITA. Not only that, but the pre-load on the differential really requires an axle housing spreader. There are ways to get around this, but better to plan for a $400 tool (see OTC). The 12 bolt is not nearly as bad, but it still involves prying and pounding. The 9" - shim packs under the pinion holder (a few bolts to loosen and tighten) and the side load is all controlled by adjusting screws. Easy... no wait, _E_A_S_Y_. And to top it off, you can change pumpkins pretty easily - even at the track. Run your 3.40s up to the track, jack up the car and drop in your 4.10 spool rear and race.
A complete, brand new 9" will set you back close to $3000! <cough>. Did I say one drawback? Make that 2.
However, you can get a housing and axles for about $900 leaving you to find a center section. Used center sections can be easily be had for less than $500... often much less. Traction control and ABS are another issue. You have to be careful what ends you pick. 4 channel ABS signal is a bit easier. I believe Moser has a setup for the 3 channel version. You have to do research.

So 9" if you can afford it - its a bit more work but worth if for piece of mind, ease of getting parts and ease to work on.
Dana 60 - leave that to the truckers. Its just not worth the hassles.
12 bolt - OK, but if you are running a hot small block with spray, don't expect a limited slip version to last long on the track. Really need a spool rear (not streetable)

**Firebirdjones** · 12-03-2011, 07:13 AM

Junk yard 9 inchers can be made to fit the 4th gens but it takes fab skills and still a fair amount of money.

They need to be narrowed to the correct width, axles made etc.... Currie makes the torque arm bracket as well as the control arm and panhard brackets, so that part is easy.
In the end it's only about $500 cheaper than a drop in unit from a supplier (depending on how resourcefull you are)

**93TransAm** · 12-16-2011, 12:41 PM

Personally i would go with the Moroso 12 bolt. strange axles and don't forget the c-clip eliminators. While your in there I would start thinking about what rear gear ratios you want and what you plan on doing with this vehicle in the long run. I'm a firm believer in building it to last or not building it AT ALL! Why waste money on the same thing more than once, when the same or less money could do the job right in the first time.