9" Rear Assembly - '66FB

hivewax said:

if i keep this 8" rear, the best option i believe is the TJ guy from eBay who has 8" center sections for $855 minimum...

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I paid $600 for my 4 pinion Traction-Lok center section, all new internals. I will see if I can dig up the contact info of the guy who builds and sells them, I bought it at Carlisle last year but think I have his card somewhere. My buddy also bought a 9" from him a couple of months after I did and think it cost him only $700. I'll post back if I can find his contact info. You should be able to do better than $855.

A friend of mine has 2 63 Falcons, one a stockish 302/auto, the other a built 302/t5z. Both started with the original 8" rears. The stick car (convertible) has broken the diff a few times with various causes. What I can say from his efforts is that in about 72 Ford changed the center section to a beefier design, along with straight axles versus the older ones that neck down after the splines. He was able to cut later model axles and respline them himself, use the later model center section, and get an aftermarket 4 pin carrier. So far he has yet to break it using a 235 drag radial and 1.6x 60' time. The friend Im referring to is pretty handy with a lathe and has his own bridgeport, you may not be so lucky. Either way its not much to have an axle cut and resplined.

Im a little surprised nobody has mentioned using an Explorer 8.8 diff. They can be had for $150 all day long around here and have 31 spline axles, disk brakes, correct bolt pattern, and most have 3.73 gears with posi. You will have to shorten one side and buy another short side axle, then have the perches moved, but its still a pretty strong cheap rear end. Only drawback is that by narrowing the one side it doesnt come out to EXACTLY the width of the original rear end. This is no big deal if youre getting custom wheels or using late model take-offs with spacers, but it may present a problem when re-using original wheels.

hivewax said:

I'm leaning towards all new 9", brakes, wheels, but your info would be great for fellow Stangers.
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get a nine with torino big bearing flanges and the 11" drum set from cobra auto. over all good braking set up and you can keep your stock ebrake cables. this is a huge plus in my opinion. no extra fab for your ebrakes.

hivewax said:

Should I replace the driveshaft to a 3" w/1350 u-joints? Or can the driveshaft be modified?
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when i upgraded to my nine, i used my orginal drive shaft. i just had it worked on to fit properly and installed the correct sized ujoints. i will sometime down the road have a new AL shaft built.

to others that might read, drums on the back look just fine compared to disc. i look at as which set up stops better. looks come second.

The 8" pumpkins almost always crack where the pinion pilot shaft enters the bearing. The area around this pilot bearing is just to thin and it will crack with any abuse and then your pinion gets flexed by the ring gear because there is no support on the pilot. This is what causes the pinion to break where it did in your rear end. You could get a new ring and pinion installed in your case and you would have the same problem after a few hard hits. About 75% of all Ford 8" case's are cracked in this area. It's hard to see an needs to be checked on any rebuild you might buy. They will run for years in this condition if not hammered on but as soon as you get after it. BOOM!