Ford 9 in rearend

[MalibuSSwagon]

You could easily spend $1000 converting a junkyard 9in, even doing the work yourself, more if you have to change axles and modify the width of the housing.

12 bolt is plenty strong.

[Rufton]

True you don't need 9". If it ain't broke why fix.

I've noticed F*rd truck 9" axles cheap on craigslist recently. I would have snagged but wrong length and lug pattern for my car and didn't wanna invest the mod time. I don't know if correct width for GM truck.

[Pyrotechnic]

The thing is, any Ford 9 inch you find in a junkyard these days is not much stronger than an 8.5 inch 10 bolt.

The legendary reputation of the Ford 9 inch is built on a few trick models that saw limited production during the golden years of muscle cars. 31 spline axles, nodular third member, daytona pinion support, etc. These were the bullet proof ones. However, the supply of these dried up long ago, and if you do find one you might pay MORE than an aftermarket unit.

Now that's not to say the Ford 9 design itself isn't great, because it really is a great design that you can easily build a strong rear from.

Here's the problem. Ford has this awesome design, but for passenger car and truck use, they didn't use the trick muscle car parts. Axles are 28 spline, grey iron center section, weaker pinion support. This is what you will get from a junkyard. It's about as strong as a 8.5 10 bolt, and will even weigh more than the 10 bolt.

If you want the legendary 9 inch strength, you need an aftermarket nodular case, aftermarket 31 spline axles, daytona pinion support, and a good posi unit. $$$$$$

[KQQL IT]

Lol only fomoco parts in my 9" is the housing and brakes.

Of course the only GM part in the engine is the block.
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[wraprail]

I have a 9 inch in my c10. Picked it up CHEAP from Pic-A-Part 10 years ago and been running it ever since. First truck was leaf springs, got wrecked so now same 9 inch is installed with triangulated 4 bar. Never have had any problems in 10 years and over 80,000 miles.
Cost was $200 complete iirc. And that included disc brakes!
I think they get around $250 for one now days.
As far as strength goes, mine is a large bearing housing, has very large taper roller bearings and 3 inch axle tubes.
Yes its 28 spline but so what. To say its weeker than a 10 bolt is bs.
Oh yeah, is same width as stock truck rear and same bolt pattern. (5X5)
I cut all the ford car suspension stuff off and welded leaf spring pads on. Thats it. (Now it has 4link mounts)
Stock rally wheels fit perfectly. Even the parking brake cable was easy to adapt.
You can find 28 spline trac-loc units at the wrecking yard cheep too.
So all this crap about high cost and reduced durability is coming from folks who have not done this swap.
Reality is this is cheap and easy to do.
Look for a late 70's (mine was from a 79) Lincoln Mark 5. You could also use the same year Thunderbird only they don't have the rear disc brakes.
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[Pyrotechnic]

Originally Posted by wraprail

Yes its 28 spline but so what. To say its weeker than a 10 bolt is bs.
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No one has said it's weaker. I did say there really isn't a strength increase over the 10.5 10 bolt though.

With that said, I do like the 9 inch design better. I like the drop out third member because it's very easy to service, or even for the sake of having a spare case with a different set of gears.

The one thing that you really gain over other rears is the fact there are no C clips. Certainly worth something in terms of strength and reliability.

So yes there are a few gains, but at the end of the day your garden variety 9 inch is still about the same in strength as a 8.5 10 bolt.

Originally Posted by wraprail

So all this crap about high cost and reduced durability is coming from folks who have not done this swap.

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Again, I don't think anyone has said the Ford is any less durable. It's just that your garden variety 9 inch is not really any better until it is made to be bullet proof.

I certainly have not done this swap either, but I have done a lot of research on it because I am planning to do it. At first like everyone else I thought a bullet proof rear was a trip to the junkyard and a few hundred dollars away. Not the case if you are speaking in terms of bullet proof.

Fact is, my truck 12 bolt right now has 30 spline axles which I have more trust in. The reason I'm choosing the 9 inch is because it's the best and most readily available platform to build from to significantly increase rear end strength.

Speaking in terms of price, a garden variety 9 inch can be had for the same price as any other rear end. A bullet proof 9 inch, well that takes some money to do. Speed cost money, how fast do you wanna go? That goes for anything.

Most people do a 9 inch swap because they have exploded every other rear end out there, or they don't want to go through the mess of exploding a rear end. These people are racing and launching the vehicle hard with stick tires all the time.

So yes, you can do a garden variety 9 inch swap on the cheap for reasons of getting the dropout third member and c clip elimination, but you haven't significantly increased your rear end strength.

It takes money to build a bullet proof 9 inch. That is all there is to it.

Originally Posted by wraprail

Reality is this is cheap and easy to do.
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Definitely, but the average person has to ask, it it really worth the time and money to end up with a rear end that's the same strength as the stock one, and heavier too? For your average tire smoking street machine, the stock rear end is absolutely fine and plenty strong. Unless you just want a 9 inch for the sake of having one or personal preference, it seems that you get into diminishing returns pretty quickly if you are doing the swap for the sole reason of increasing strength. Even with the coolness of the drop out third member, the guy with the average street machine never touches the rear end other than to change the gear lube or fix a leaky rear cover gasket. Even on the topic of rear disc brakes, there are so many conversion kits out there that swapping a whole rear end to just to get them is not necessary.

My point for posting all this is to clear up some common misconceptions about axle strength.

-The legendary god like strength of any old 9 inch you can buy for $50
-All 10 bolts are junk and will explode if you look at them wrong
-All 12 bolts are the god of GM rear ends

We've all heard this stuff before. I find it a lot more useful to look at the mechanical aspects of each design and decide which is one is REALLY stronger. I could care less about brand names and rear cover bolt counts.

[andrewmp6]

A junkyard 9 inch your probably gonna find a lincoln versailles which is 28 spline and had a avg gear ratio of 2.80.Most truck 9 inches are stronger but are pricey now because of off road guys wanting them.And ford replaced the 9 inch for the 8.8 around 86 or 87 so even the truck ones are harder to find today too.I'm a ford guy most now use the explorer 8.8 in the early mustangs because they are cheap to get at a junkyard today vs a 9 inch.

[wraprail]

I did the swap cuz it was cheap and easy. My 10 bolt was worn out and had 3.08 gears. Yes I could have just swapped in another 10 or 12 bolt but anyone could do that. Also I wanted disc brakes which the Lincoln already and a lower gear.
The Versailles rear is 5x4-1/2 bolt pattern and narrower than the truck housing.
The Mark V is the same width and bolt pattern as the C10.
In my case since The 9 inch cost the same as a 10 or 12 bolt so I went for it.
As I said, it has worked great for me, the disc brakes are awesome, i have the option to swap gears if i desire and its just cool. Unusual. Different.
Nobody suggested this swap to me or recommended the Lincoln as a possible option. I did not read anything about this swap. I had the idea, went to the wrecking yard with a tape measure and a note pad and put this swap together. There is a certain amount of pride and satisfaction you get out of doing something like this and thats probeley the biggest reason I did it. Cuz its *****en. Lol
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[naphtali5725]

wrap,
what year Mark V would have a 9 with the 5x5 bolt pattern?

thanks

Originally Posted by wraprail

I did the swap cuz it was cheap and easy. My 10 bolt was worn out and had 3.08 gears. Yes I could have just swapped in another 10 or 12 bolt but anyone could do that. Also I wanted disc brakes which the Lincoln already and a lower gear.
The Versailles rear is 5x4-1/2 bolt pattern and narrower than the truck housing.
The Mark V is the same width and bolt pattern as the C10.
In my case since The 9 inch cost the same as a 10 or 12 bolt so I went for it.
As I said, it has worked great for me, the disc brakes are awesome, i have the option to swap gears if i desire and its just cool. Unusual. Different.
Nobody suggested this swap to me or recommended the Lincoln as a possible option. I did not read anything about this swap. I had the idea, went to the wrecking yard with a tape measure and a note pad and put this swap together. There is a certain amount of pride and satisfaction you get out of doing something like this and thats probeley the biggest reason I did it. Cuz its *****en. Lol
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[wraprail]

1979
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[naphtali5725]

Originally Posted by wraprail

1979
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thnx wrap

[wraprail]

NP
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[Restomod]

I have a 1985 Chevy 2wd 1/2 ton stepside and I was considering putting a 12 bolt in my truck until I read some of these posts. Now I think I will stay with my 10 bolt. I have an open rear with what I believe to be a 2:56 gear. I would like to change it to a 3:73 posi. Any suggestions on where to obtain a complete kit to do this upgrade or a reliable source for a complete rear end? Seems I can find rear ends for cars all day but am not having much luck finding one for my truck.