8 3/4 vs 9" cost-wise

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YoungBlood said:
Think seriously about this.

Here's what I have spent from collecting parts: (I am picky and didn't screw w/ too much used sh*t)

A-Body housing (REAL, AUTHENTIC):........................ $500.00
Moser Alloy Axles (the good ones):............................$400.00
NOS 3.23 Gears (Never Used):...................................$220.00
Eaton Tru Trac:........................................................$545.00
489 Case:...............................................................$200.00
B-Body 11x2 Brakes (Refurb plates, new everything)...$335.00
Crush Sleeve Eliminator fronm Dr. Diff..........................$30.00
Yoke.......................................................................$120.00

I still need to spend $500 on labor/bearings/seals/etc.

Total will be around $2850. I love my car and staying true is important to me.

You can save big depending on where you live (parts demand/labor cost) and if you aren't super-concerned about anything failing.

I'm spending this money so I only spend it once.

In the end, even if you knock off $500 from what I have in mind, a complete B-Body rear could potentially be had for 1/10 the cost.

Dana would be close in cost. A 9 inch... well my dad could have got me a new unit through his company for $800, but you get the point. Call me stupid, it's okay. I regret nothing.
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that is about what ill have in my bullet proof 9" with billet center section custom for my application. Not a single used piece in it.

Is say it depends on ones ultimate power and usage goal. Mine is 1500hp+, op probably not so much?
 
My custom width Strange 60 with perches welded and True Trac upgrade was $2300 shipped.
 
Turbofreak, my end goal is MAYBE 300-350. But realistically I'll prolly hit 275ish. As far as breakin, to me is a non-issue. I just want to chuck the 7 1/4 since the 360 wud destroy it! I wudnt mind a Dana but I'm still tryin to get an 8 3/4 since it'd b cheaper. I'm actually goin for the street lynx rear suspension so I need a 9", Dana or 8 3/4
 
turbofreek said:
I put in a 9" in mine. It's all new and was pricy, but it will never break on me. Mine was custom cut to match wheel offset for a particular look I was after. I also won't have to hunt used classifieds to pick up a part. I can just call any parts dealer and get it quickly. Food for thought for you.
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When the 3rd bearing gets a little play in it, the entire pinion rips out from the diff and takes out the shaft, and trans and exhaust. . . .

I have yet to see someone catch when the 3rd bearing is getting close to going bad BEFORE the other happens. . .

Get the Dana 60 if you want never break without needing a shaft and trans. . .

9" is not bullet proof, when they go, they cost you a complete driveline.
 
Supershafts said:
When the 3rd bearing gets a little play in it, the entire pinion rips out from the diff and takes out the shaft, and trans and exhaust. . . .

I have yet to see someone catch when the 3rd bearing is getting close to going bad BEFORE the other happens. . .

Get the Dana 60 if you want never break without needing a shaft and trans. . .

9" is not bullet proof, when they go, they cost you a complete driveline.
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Stock non nodular 9" yes, but a billet aluminum no.

To the op, a b body 8 3/4 cut down will be the best suited and fairly cheap for you. Since your not needing anything to strong for that power range and goal.
 
Race shops or driveline shops around here will shorten a rear for about $150. We used a chop saw to cut mine down, ground down the old ends, they are just butt welded on, then took it to a race shop. He put the jig in it and welded it for $50.
 
turbofreek said:
Stock non nodular 9" yes, but a billet aluminum no.
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I have seen plenty of the nod cases do it also, and even some break the caps and stamp the housing.

If the 3rd bearing falters you will have even the daytona pinion come ripping out of the case, nothing can change it from happening if the 3rd bearing falters, all by design, that 3rd bearing suffers and the pinion can move just a bit, snap and forward it comes..

Happens a lot, but people think the 9" is better, loading the bearings more than other diffs and carrier.
I am gonna have another one that just ripped itself apart tomorrow, and i'll explain to that customer step by step the pros and cons of that diff and he'll understand why when they break, they grenade everything (it also was a nod case, daytona pinion).

A dana, 8.75, 9.25, 10blt, 12blt have a bearing failure and you may need gears, those 3 will give you a warning, i have never seen them shoot the pinion thru the shaft and kill a trans though, i did see even the aam 14 bolts do the same thing, and even 1 of the amm modernized 14 bolts kinda get the pinion out of the case.
 
I think you can do a 8 3/4 for alot less if you shop around. I got one out of a 73 town and country for $110, 489 case 2.76 gears. Paid $145 to have it shortened and new perches installed by Moser and $110 to have the axles shortened and re-splined. Had about $150 in shipping charges. Got a 3.23 741 gear set for $75 and have about $100 in the brakes and lines and paint. Am still looking for a good sure grip to build the 489 case but for now I have a nice rear that I can work with for right around $700. The drive shaft had to be shortend but that cost is the same no matter what rear you use
you also should plan on a new flex brake line an U bolts. Probably a few other things i forgot, but alot of the cost is going to be there any time you change the rear out.
 
9" compared to a 8 3/4 is a joke...sorry to spoil the fun but get the 8 3/4 or the dana...I am so done with ford 9" that it aint even funny.....first off the lil pile of crap that houses the rear bearing breaks like it was there for look's...then the pile of crap rob's more horsepower than an 8 3/4.... dana robs some h/p but you cant break it and if you can break it then you the man :thumbup:
 
waggin said:
9" compared to a 8 3/4 is a joke...sorry to spoil the fun but get the 8 3/4 or the dana...I am so done with ford 9" that it aint even funny.....first off the lil pile of crap that houses the rear bearing breaks like it was there for look's...then the pile of crap rob's more horsepower than an 8 3/4.... dana robs some h/p but you cant break it and if you can break it then you the man :thumbup:
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How does a differential rob horsepower?? Just curious...
I'm guessing the larger ring gear takes me more power to turn? If that's the case, it can't be much...
 
Pinion location in reference to the ring gear.

The 9" is at the best at robbing the most hp and putting the most pressure on the internals.
The factory 9" is even worse, but they have the best contact, and most drag, the aftermarket gear makers lose some of the drag by there gear design and do that thru the contact, but they only lose a little and the 9" is still the #1 power robber, the 9" has a ton of gear choices and pro gears making it easier to want to use.

The gm 12 bolt is the least at robbing hp, then the dana and 8.75.

The closer to center the pin is located to the ring the less power loss and pressure.
 
i flat out cannot use any GM parts in my dart cuz my chevy buddy will spot it an never shut up. hes not familiar with ford so hed never know! guess il continue my search for a B body 8 3/4 an shorten it. how much would it cost, roghly to shorten? i know all shops are different but ball park am i lookin at $300 for a b body rear and $200 to shorten?

Also, what if i get a rear that is missing brake components? or theyr damaged? can i order whole drum brake set-ups(like, EVERYTHING needed to put new drum brakes on) or do i need to puzzle piece parts together?
 
I'm using a truck 9.25 axle. Had it narrowed & replaced everything inside. Moser axles, Auburn Sure Grip, 1350 pinion yoke, new drums, etc. Set up was easy. I have about $1200-$1300 total. Got tired of looking at over priced A-body 8 3/4.
 
I am building an 8 ¾ right now. Here is what I have in it so far…

Real a-body housing - $200.00
Dr. Diff BBP axles w/ bearings - $300.00
742 with rebuild clutch SG and original 3.23 gears w/big yoke - $350.00
Shock plates and U bolts came with 742/3.23 deal- $0.00
Brake lines - $20.00
I still need brakes, brake T, vent bolt, and hardware…

I have no shipping in any of these items, and it took me over 6 months to find a good deal on the 742 center section, but they can be found…
Hope this helps!
 
KramerSwinger70 said:
i flat out cannot use any GM parts in my dart cuz my chevy buddy will spot it an never shut up. hes not familiar with ford so hed never know! guess il continue my search for a B body 8 3/4 an shorten it. how much would it cost, roghly to shorten? i know all shops are different but ball park am i lookin at $300 for a b body rear and $200 to shorten?

Also, what if i get a rear that is missing brake components? or theyr damaged? can i order whole drum brake set-ups(like, EVERYTHING needed to put new drum brakes on) or do i need to puzzle piece parts together?
Click to expand...

LOL, you got one of them Chevy buddies too!

I have a set of the big brake backing plates with the necessary hardware to assemble brakes I'll sell cheap so if you find a rear that needs them PM me. I don't have drums, shoes, or small hardware but you'd probably need to replace all that stuff on any rearend you buy anyway.
 
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