01 SS Jay

I want to go ahead and investigate what it would take to make an 8.5" rear for our cars. I talked to a friend that owns a machine shop, and he's willing to help me with this. I dont want to go the $2200 12 bolt route (I have traction control) and since my plans wont exceed 450hp, I want something cheaper. Give me some feedback, guys.
Thanks

Pro Stock John

iTrader: (34)

Devil's advocate coming thru... <img src="gr_images/icons/wink.gif" border="0">

Ideal scenario...
-comes with a posi
-comes with 3.42 or 3.73 gear

Otherwise...
+$150 for a gear
+$450 for a posi or a locker

I was told that the 4.3 S10 5spd trucks have a 8.5 rearend, and I would guess they would also have 3.73's stock. Might be worth checking out.

You'll have to cannabalize your stock rearend for the traction-control reluctor wheels which are on the end of each axle. You would also need your brake backing plates.

Other thing is the torque arm setup, LCA brackets, and spring perches all have to be set up and welded.

As you do this keep in mind you can get a 12 bolt for like $2100. Good luck!

I have a Moser 9" I paid $1950 for it a few years ago.

I think it's doable.

01 SS Jay

Yeah, the idea I was having was that custom axles will be a must. I was thinking of just cutting the ends of the axle tubes off the fbod rear, welding them into place on the cut 8.5" rear, fabbing a tq arm mount, and adding the new axles. Anything im missing here??

[ February 21, 2002: Message edited by: Jason ]</p>

onfire

iTrader: (17)

I'd look at the 1999 to 2002 1/2 ton Chevy Truck rear. They have disk brakes, an 8.6 inch ring gear (upgraded from 8.5 in 1999) Eaton posi and should be cheap from a junkyard....most have 3.73 gears...some 3.45 and 4.10. The torque arm will be the b*tch.

WFO_SS

iTrader: (2)

v6 s-10s have 3.42 (except 4x4s, i think...maybe those have 3.73s)
4 cyl s-10s have 4.11s.

JS

iTrader: (4)

PSJ is correct.Its not worth the hassle or $$$ to try and fit a 8.5 to our cars.Buy the 12 Bolt or 9in and be done with it.

JS

01 SS Jay

Dont agree with you there JS, I think its a great idea and someone needs to pursue it. For those of us who really dont want/need over 400hp but still like to run at the track every once in a while, a 12 bolt or 9 inch is overkill, especially $2000 worth of overkill. If there is a way to get something stronger than stock for under $1500, its well worth the time and effort. Not everyone has wallets like you guys do.

nbm99ta

I was talking about this to a friend of mine who owns a chassis shop. This guy builds tube chassis's, custom roll cages, headers, rearends, etc, etc. He was telling me that he can make almost any rearend fit in any car. He has the precision equipment to put it together. If I provide the rearend, it will still cost over $1000 for everything. About $400 of that will be custom axles, if he can't make them.
I was thinking about an 8.5" truck rearend, or a Ford 8.8"

gm_jim

[quote]Originally posted by Jason:
<strong>Dont agree with you there JS, I think its a great idea and someone needs to pursue it. For those of us who really dont want/need over 400hp but still like to run at the track every once in a while, a 12 bolt or 9 inch is overkill, especially $2000 worth of overkill. If there is a way to get something stronger than stock for under $1500, its well worth the time and effort. Not everyone has wallets like you guys do.</strong><hr></blockquote>
I couldn't agree more. For $1500 a fabricator could probably sell a hundred of these. Basic economics says as the numbers produced go up, the cost per unit goes down. On the Impala SS board they beat the heck out of their 8.5's and they hold up. I ran a 500HP 454 in my second generation Trans Am, blew up several Super T10 4 speeds, but never a single problem with the 8.5 in that car. Keep us posted - I'm all ears.

Crazyquik

Ford 8.8 is too narrow.

Pro Stock John

iTrader: (34)

This is like the fifth thread about this in six months.

I have not seen anyone do any legwork.

Two years I measured my 89 5.0 rear housing, and it was like 1.5" too narrow on each side. I think most of you would want to keep stock backspacing with your wheels, so let's see some of you guys get dirty LS1Tech style. Take a tape measure and start measuring the rearends in the suggest vehicles.

Now if you can get a boneyard Caprice rearend for say $100, that's a great start. But what is the length of those things?

01 SS Jay

Yeah, I plan on it. I used to work at a junkyard, so Im going to snag a used 8.5" out of something and do some measuring. Probably this coming up weekend ill have time to do it. The way im looking at it, a donor fbod rear and basically the center section out of 8.5, plus custom axles should do the trick. Might not need custom if i can find correct length 26 spline axles. Im hoping that cut and re-welded axle tubes (if done properly) will be strong enough than making brand new ones. I suppose I can do some external bracing on them if necessary.

Terry Burger

iTrader: (4)

Guys if it was easy someone would do it. If you want cheap (and easy), do a cheap ford 9". The housing/axles are $900 from Moser, then just buy a junkyard 3rd member for $200-300 and you're set. I did that in my '93 Z28 awhile back.

01 SS Jay

Does that have abs and traction control setup on the 9"? I know thats a low buck approach, and I did already look at that (speaking of which, friend of mine has a 9" hogs head with a 3.25 for sale $350). I want something as close to stock as possible with just a bit more *** to it.
I can get a mini spool for $100 for the 7.5" rearend. Hrmmmm.

Dwain Brammer

I know back in the thirdgen days, alot of people looked to do this and most had problems.
1) Nobody at the time made carrier housings that had the torque arm mount "Cast into it", so you'd have to spend big money to find a COMPETENT welder who is experienced in welding cast iron (NOT EASY).
2) Some people used a girdle type deal that bolted over the diff cover and worked as the rear mount for the torque arm. These were fabricated pieces that were expensive and often broke.

This is what I've been wondering...SLP & GM hired Dana to make the Dana 44 rears that came in the original Firehawks and were then sold by GMPP over the counter. They stopped selling them 5 or 6 years ago. SLP had some more made about a year ago and started selling them again.
So if enough people were to get together and contact Dana about making a 4th Gen Dana 44 that allowed for ABS (and TCS if necessary), they may do it. The Dana 44 is superior to the 8.5" 10 bolt because it uses bolt in axles, instead of c-clips. SLP was selling them for 1600, so what do you think they got them for??? Alot cheaper than a 12 bolt costs us, huh!

gm_jim

What's the ring gear diameter on the Dana 44?

Dwain Brammer

8.5"

Jim98TA

I am not 100% sure, but I believe the 7.5 rear axle tubes are actually slightly smaller in diamater than the 8.5 tubes. That could be an interesting welding job.

I have a 7.5 g-body rear on the garage floor, and an 8.5 gn rear in my car, I will have to take a closer look at em....

Nine Ball

iTrader: (38)

pssst.... The Ford 8.8 from a 5.0L Thunderbird is wider than a Mustang's.

Brooke (99RedHawk) had one given to him and did alot of research on getting it modified to fit the Firehawk and have stronger internals added and it was going to cost over $1500 when all was said and done. And it wouldn't fit as well as a 12-bolt designed for our cars.

Unless you can get a rearend under that car for $1000 or less, just step it up and buy a 12-bolt. I'd rather have my 33-spline, perfect fitting Moser for $2100 than a half-*** stock intenal 8.5" for $1500.

Tony

01 SS Jay

Very valid points. Yet $ is the driving factor here (for me anyway). Half-assed depends on how you do it. $1500 for something that is adequate to the purpose is money well spent imho. Im tossing a few ideas around with my machine shop guy, and we have a few things to try.