rearend options...

I just got off the phone with IWE and the guy there was telling me a few interesting things. One was not to even consider the 9" because is whines like a biatch. Second was that the 12 bolt housing is hard to come by. So he recommended a 8.5" 10 bolt rear. He says that it will be able to handle the power like the 8.8" 12 bolt rear. They use all the same parts. The only difference is the 2/10" ring gear difference. Even the bolts even out, so to speak. The 12 bolt just uses smaller bolts while the 10 bolt are larger bolts. That didn't make much sense to me but whatever.

Anyway, I need some feed back from the rear end experts here. Do you think the 8.5" rear is actually as strong as the 8.8" 12 bolt?

Thanks
-Ken

Well a couple of things
I am not sure why the 9-inch gets a bad rap for noise. It has been running around under Fords since the fifties. Possibly there are numerous aftermarket gears sets or pumpkins that aren’t quite up to snuff.
Be prepared to spend some cash as most nine inches are 28 spline axles with substandard or no posi.

Although there are few 12 bolts laying around there are at least aftermarket housings that have torque arms mounts cast in.
Factory, they are at least 30 spline axles.

The actual gear sets in the corporate 8.5 10 bolts are plenty strong.
Other than the 90'ish and up "B" body the 8.5 used "fair" 28 spline axles.
30-spline Eaton posi's are readily available but use some goofy low angle bearings to fit them in the 8.5 side housings.
You still have the issue of trying to mount the torque arm.

As for strength, the 8.5 with 30 spline axles seem to stand up to a number of very heavy Impalas and Caprices.

As for shear size the 9 inch may go under an "F" body but it leaves little room for anything else.

No matter what you do under there are going to be custom work or parts. But to answer your original question, I believe a correctly built 8.5 would be up to the task.
Gerry

Once the car is finally dialed in it should be pushing out ~400 rwhp then adding 200 shot of n2o in a year or two. Do you think the 8.5" 10 bolt will hold up to it.

In other words... will the 3/10" diferance from that 10 bolt to a 12 bolt really make that much of a diferance in strength?

Once the car is finally dialed in it should be pushing out ~400 rwhp then adding 200 shot of n2o in a year or two. Do you think the 8.5" 10 bolt will hold up to it.

In other words... will the 3/10" diferance from that 10 bolt to a 12 bolt really make that much of a diferance in strength? IWE is right about the 8.5" its a great rearend too. i got one and ill be running on in my combo (see sig) ill be running it into the 9's and pulling the tires on it, it will get the job done. its a good cost effective rearend. :cool:

Number one issue is to be honest with yourself about the aplication you plan to use it for. For example, if you want to try some open track or auto cross events, you won't want to use a locker and 35-spline axles.

But also, I was told "better to over build it, than under build it."

Andy

Shut up Andy. I know one 95 TA with a 8.5" and I've seen 8.5's and 12 bolts side by side, they look the same, except the aftermarket 12 bolts look like beef!

Also, I have over 400RWHP and I've dead hooked tons of time and beat on my 10 bolt 7.625" with 4.10's with not a single wine or any problems, I think a lot of it has to do with how well built this stuff is.

oooookkay Matt :rolleyes:

Shut up Andy. I know one 95 TA with a 8.5" and I've seen 8.5's and 12 bolts side by side, they look the same, except the aftermarket 12 bolts look like beef!

Also, I have over 400RWHP and I've dead hooked tons of time and beat on my 10 bolt 7.625" with 4.10's with not a single wine or any problems, I think a lot of it has to do with how well built this stuff is. and a 8.5" is that much better then a 7.5". alot of it is to do with the housing strength itself also. its pretty similar to a ford 8.8, and they are strong rearends, lots of them going 8's. i beat on my stock 8.5" with gears for 4 years and when it came apart it had no signs of wear, and thats with many years of slick launch and burnouts and street racing etc. and that was bone stock. if you get the diff support cover, weld axle tubes and put a good posi in there or a spool, with some good axles, you will never have to worry :)

oooookkay Matt :rolleyes:


LOL :lol:

Also, I have over 400RWHP and I've dead hooked tons of time and beat on my 10 bolt 7.625" with 4.10's with not a single wine or any problems, I think a lot of it has to do with how well built this stuff is.

It's only a matter of time Matt, trust me on that one.

Ken, I have heard the 8.5" 10-bolt is almost equal to a 12-bolt. But the costs to weld one up to fit into your car? I don't know if that's worth it really. I'd also think twice about IWE, I have had some bad luck with them in the past.

I spoke directly with the guy that does all their custom work and he says that most of the parts are the same for the 8.5 and the 8.8 rears.

Cost wise he said it would be about the same price. The only diferance would be that the 10 bolt housing is cheaper than the 12 bolt. There would be some custome fabing for either rear so the cost of making it a bolt in app. is the same.

Well Moser & Strange make bolt-in 12-bolts for your car, I think Moser even makes a bolt-in Ford 9-inch for your car as well.

I don't think there are any bolt-in 10-bolts for F-bodies

How come youre leaning away from a bolt-in unit?

I'm just leaning towards whatever will cost me less without sacrificing the durability or strength.

I'm looking to get one in Feb. so I'm still shopping around to see what I can get. So far it looks like whatever I choose its gonna cost around 3 g's to get it to my house ready to bolt in.

It can be done cheaper just takes a llittle time to look for the right parts. I built my 9 inch for under 2000 3 years ago. The Housing and axles from moser were around 900. All the rest of the parts were picked up locally minus the gears for 250Cdn. Gears were just ordered from summit racing. All in all it costed me less then 2000 cdn for my bolt in Moser 9 inch with a detroit locker ,35 spline axles and Nodular case. :D



Happy shopping

It can be done cheaper just takes a llittle time to look for the right parts. I built my 9 inch for under 2000 3 years ago. The Housing and axles from moser were around 900. All the rest of the parts were picked up locally minus the gears for 250Cdn. Gears were just ordered from summit racing. All in all it costed me less then 2000 cdn for my bolt in Moser 9 inch with a detroit locker ,35 spline axles and Nodular case. :D



Happy shopping

Did you build it yourself?

A buddy of mine helped me set the gears over a case of beer. I do everything beside gears cant stand the damn things. Even if that wasnt done for free most shops will charge about 200 bones to set up a 3rd member on a 9 inch. So added into the cost it still prob would have been under 2000 or damn close. My opinion is go 9 inch if you can the housings and axles are your big spenders. Most of the other stuff you can easily find locally for a good price. Plus nothing beats the ease of changing out a set of gears out of a 9 inch or its stength and reliability;)

i stand by my 8.5 10 bolt :cool: plus its more power to the ground :p

how did you get that put in? Did you get a shop to do all the custom fabrication, or do it yourself?

I'd love to have a 8.5" 10 bolt, keep my 3 channel ABS and still get to keep my favorite type of diff, the Torsen T2-R.

when i was shopping around for the rear, this is what I found out.....

9" Ford's have a ton of Diff selections too, but you basically lose 3 channel ABS with it, unless you rig up the reluctor ring outside the housing, which someone has done in the drivetrain forum..

12 bolts don't seem to have the same number of diff options availble.. Although if your drag racing, you could find one you like..

And then some camaromustang challenge folks use a Dana Rear..

But, in the end, I think I'll just save some more cash and get a used C5 instead.. (for the street)

BTW, if someone wants to pick up a cambered 7.5" 10 bolt, thats been sitting in my backyard for over an year in oregon, just drop me an PM! (mounts are not stock) It was out of a camaromustang challenge car, from Richard Pryor (not the comedian lol)

ended up just putting another 7.5" 10 bolt in there, with a t2r and 373's.. I rarely drag race, try to go autox more..

i stand by my 8.5 10 bolt :cool: plus its more power to the ground :p

I am sure i will survie with the 10-15 HP loss. There will be plenty of power left over to turn the wheels ;)

I've heard that the Ford 9" howls really bad. Is that true? I believe it was to do with the head warping somthing when the weld on the torque arm bracket.

I know a few people on here have gone with the 9" but you also are some of the hardcore racers. Would you recomend it for a street/strip car?

Also... what are the options and opinions with the C clips on the 12 bolt? I've read that the eliminators tend to leak. Would it be any different using the bolt on versus the weld on type?

Correct me if I'm wrong but I would have to do the C Clip eliminator for both the 8.5" 10 bolt and the 8.8" 12 bolt.

Thanks Guys!! All your input is really helping me out! :thumb:

My 9 inch had no whine whatsoever i believe andys might have had a little. It all depends on how it is setup. the beauty of the 9 inch is if it whines it doesnt mean she is going to break anytime soon ;) If all is setup well the noise should be minimal on whatever diff setup you run

Mine howled but its because they are Richmond gears and also 4.30s are a typically noisy gear.

Either way Ken, you are going to have drawbacks to any set-up. I wouldn't trust any 10-bolt to a high rpm clutch dump and sticky tires, the 12-bolt has proven to be a weak link (by Payam and many others I have talked with on LS1tech) and the 9 inch sucks a bit of power. It might be something to consider for "wow-factor." A 9-inch looks pretty trick under an f-body. I think its the coolest part of my car.

Andrew

A 9-inch looks pretty trick under an f-body. I think its the coolest part of my car.


LMAO

The 9" looks to be around $300 - $400 US cheaper too... so far. I like the idea of the 9" also... I just dont want my car to sound like a bus. ;)

Payam bent an axel tune, this is because the Strange 12 bolts use stock 10 bolt axel tubes, while my Moser 12 bolt use huge 3" puppies or something, but its quite a bit heavier in weight then a strange 12 bolt, I'm sure it can take the abuse no problems.

But yeah, I think its the Richmond gears that have to go in your rear end Andy, my 12 bolt has richmonds too and it wines, its not that bad but it can get to you if you have a head ache that day and end up driving the f-body LOL, my 3.73 richmonds don't wine under decel/accel but coasting at about 100 clicks it gets pretty noisy, this is when the stereo knob comes into play. Some day I'll put GM gears in there or something.

i got 4.10 richmonds in my 8.5" and they dont whine, check your grear back lash :p

i dunno, ill be putting a crap load of power through mine this year, and running a trans brake on it with slicks. im sure if i can make it live it will be good for the rest of you :cool: