8.5" rear strength

[marcar1993]

I know I want to go with a dana 60 in my car for sheer strength, but it just doesn't seem to financially feasible. They start at $2340 + ~300 for a non-clutch type posi (they suggest it for any track use) + ~300 to ship it still brings me to around $3000. Ouch. Then I still need to set up brakes on it.
I know all about the million other options that "bolt right in" and so on, but that isn't what I want to know.
I have a 4.10 open 8.5. I priced a detroit truetrac locker and 30 spline moser axles for it. I figure that combined with f body disc brakes (as an axle retention method since it has c clips) could be had for ~$1000 plus some time.

The real question: What kind of power levels would an 8.5 ten bolt be capable of with a detroit truetrac and moser 30 spline axles? This is a heavy car with a stick. I would say it makes roughly 400hp, it will make more down the line. It gets abused. I dump the clutch. It will see slicks.
Am I nuts? Or is the 8.5 up to the task?

 

[88hurstolds]

The A-body guys have been dumping 8.5's for 12 bolts and Ford 9's for years if that tells you anything.
Ford 9" is the way to go IMO, sell it to someone else and use the money for one.
I don't see what all the hype is around the 8.5...

 

[bob64]

Slicks and torque of the engine is your worry. Some people have luck with 8.5, and more don't when your talking track.

I have had bad luck with 8.5's on the street let alone on the track, in different vehicles running BB. When they exploded there was no recovery only replace it all.

I seen summit has G-body 9" housings for around $500usd so there is a thought.

 

[DRIVEN]

I don't think of an 8.5 as a crappy rearend but it has it's limitations. After all, plenty of hot Fbodys beat on them in the 70s. But we also can't ignore that GM is a big corporation and the only reason the risky Gbodys got an 8.5 was fear of warranty claims. If they were trying to build cars good instead of profitable, every G would have gotten a 12 bolt.

 

[TURNA]

Ford 9

Even GM woke up and realized they are the best rears for the $$

Take a look under the new COPO Camaro

 

[UNGN]

8.5's don't like shock loads. An 8.5 that will live forever in a 9 second foot brake car could be broken by an 11 second clutch car.

If you are on a budget with a manual trans, 9" Ford.

 

[olds307 and 403]

According to a diff builder, the 8.5" 10 bolt is nearly as strong as the 8.875" 12 bolt rear. Geez, you guys are jumping on a 8.5" like it is that 7.5" dud most of our cars got. Seriously the 9" is not cheap complete either, price a 3rd member, axles and bearings. Marvin should be able to recoup the cost selling the 8.8 and 8.5 rear ends to help pay for it and it will be stronger.

 

[87National]

I know I want to go with a dana 60 in my car for sheer strength, but it just doesn't seem to financially feasible. They start at $2340 + ~300 for a non-clutch type posi (they suggest it for any track use) + ~300 to ship it still brings me to around $3000. Ouch. Then I still need to set up brakes on it.
I know all about the million other options that "bolt right in" and so on, but that isn't what I want to know.
I have a 4.10 open 8.5. I priced a detroit truetrac locker and 30 spline moser axles for it. I figure that combined with f body disc brakes (as an axle retention method since it has c clips) could be had for ~$1000 plus some time.

The real question: What kind of power levels would an 8.5 ten bolt be capable of with a detroit truetrac and moser 30 spline axles? This is a heavy car with a stick. I would say it makes roughly 400hp, it will make more down the line. It gets abused. I dump the clutch. It will see slicks.
Am I nuts? Or is the 8.5 up to the task?

400 crank hp or to the tire? Either way, you will be fine with the 8.5". Turbo buick guys run 10s with the completely stock rear and 9s with aftermarket axles, gears, carrier, etc.

 

[MrSony]

I dont know about where you live, but around me (down the street actually) I live near the Fairgrounds and there used to be all kinds of guys racing g bodies and what not. Sometimes if they were amateurs too in over their heads or had a bad wreck, they'd sell off the parts of the cars that were still usable. At least once a month a 9 inch housing with the g body brackets and perches welded on pop up for a few hundo.
If 8.5s were as common as 7.5s, I'd say go for it. But since they're so far and few inbetween, plus most dillholes won't take less than 1300 for them (broken or not), the 9" is really the only way to go. It'll be cheaper in the long run, especially if you factor in the cost of rebuilding a c clip rear end probably more than once.

 

[64nailhead]

http://www.quickperformance.com/GM-86-10-Bolt-Posi-Gears-Bearing-Kit-Package_p_20406.html + $260-285 for a set of Moser Axles.

When we bought our parts from Quicks the price included the freight.

I have no experience with manual's, but I'd find it hard to believe that the 8.5 won't withstand a 400HP powerplant. For that matter, for a 400HP powerplant I'd leave the 7.5 in there and upgrade it to 28 spline posi from a 4 Gen Camaro and a set of S10 2WD axles if budget was a concern.