Anyone looking for a nice rear?


Comic Book Super Hero
Feb 16, 2009
Western MN
My intent is that an 8.5 is not significantly worse than a similar equipped 9" or 8.8. The reason a 9" has some legendary strength reputation (in my opinion) is that they were stronger than similar options in the 70's and 80's just due to the fact they were typically configured for high HP or high weight stuff and there was less HP. The reputation exists today because they are stronger today because the OEM market has entirely dried up. Nobody is using OEM case 9" stuff anymore or stock axles. The reason it's all strong is because it's specifically designed to be for the aftermarket hot rod market so there are more 35 spline nodular iron cased 9" made today going into 750hp cars than OEM 31 spline ford cases going into 400hp cars. The 400hp today would probably blow up most 1973 era 9" stock stuff but none of it exists in the salvage yard anymore so it's all significantly more HD than it needs to be.

Yeah, I broke my 8.5 but I would have broken a similar economically built 8.8 ford or 9". If I put $2800 into a 9" that showed up in a crate in my driveway or built my own $1800 9" with as much factory parts as I can scrounge up it would perform the same as my $1200 8.5 that I have some time in. I could spend $3500 and get a 9" that is significantly better than my $1200 8.5 but it's all aftermarket.

And what I have found out over anything is that a properly set up chassis and suspension is more beneficial to making parts live than the parts themselves. If the instant center on a car is wrong, tire pressure needs tweaking, shocks need adjustments, or things along those lines you are going to break anything you put at it. If the chassis is set up right and you put $1000 into shocks and control arms you can cut $1500 out of your rear end and go faster. Tossing extra money into super HD rear end parts makes the rear end live sure, but it's more parasitic loss, weight, and you just break driveline and trans parts because whatever is causing the rear to break still exists.

How many violent NA 12 second big blocks had 40 spline gun drilled dana 60's in the 80's and broke parts? A lot.
How many 8 second turbo cars run on 28 spline 4 lug axles today and never break parts? A lot.
I lot of that is attributed to smart chassis tuning and power management. I just feel like a lot of 9" stuff is just institutional inertia and the reason 9" sell good today is because they sold well in the 80's.

No singling anyone out, just what I have learned from my adventures.
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Amateur Mechanic
Sep 24, 2020

I had planned to build some but...
I see VEGE/ATK sells a lot of remanufactured 8.5" 10-bolt for truck applications.

I'm not sure it would be impractical to grind off leaf spring perches, bracketry, etc., and adapt the currie bracket kit (made for Frod 9") to fit.... Seeing that you spliced the 7.5" axel tubes to the 8.5" housing, I don't see why couldn't buy a wider track rear and cut an inch or two out of the axel tubes and re-join with a sleeve of rolled plate and fillet welds. Buy new axels. Should be able to do this with the pre 1977 A-body 10 and 12-bolts too. Not sure why there are so few choices (ford9 or, the ford9 or the ford9 or a $5k Moser 12 bolt or $5k S60).

I think you could sell more of them for $2500 than you could make.

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Jun 15, 2012
Florida Beach
Biggest thing I've seen with the 9" is how fast you can change out the chunk to get a different gear ratio in, if you have a second or third on the side already setup. Know a few who do that.

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