Which Type of rear end do you recommend or prefer?

I am putting together a turbo engine (450 hp) with a standard shift transmission for my 88 Firebird. Of course I have a few stock 7.5 inch 10 bolts on hand, along with a 9 bolt Borg Warner. I have up until recently been saving for a Strange Dana 60 rear to bolt in. I want to use the stock suspension setup (but not stock parts.)

Recently I've been searching the forums again and I have seen a few articles extolling the virtues of the 9 bolt. Some are beefed up with Aussie parts and according to the Street Machine magazine article (also from Australia) it seems that this rear can be built to take what I am going to do to the car.

I will be putting aftermarket axle shafts in any rear axle which goes under the car.

So, what combos are you guys recommending?

 

I would go with a Dana 44, 12 bolt, 9" or as a last option Dana 60.
I listed them in the order of strength, weight and power loss.
Choice is yours but I'd move away from a stock rear unless you drive like grandma..
I run a dana in one of my cars and a 9" in another.

 

Ford 8.8" custom built.

My 8.8" has axle tubes from a 9" so it has the pressed in bearings. It's a lot lighter than a 9" housing and the power consumption is a lot less. It's a very stout rear end and you won't break it with 450hp.

 

This is how I have been leaning as well. I really don't like the Ford 9" much. Something about power loss driving through the gear sets...

I certainly do NOT drive like Grandma; well, maybe like the little old lady from Pasadena...

I tend to be really hard on my personal cars. I'm nice to the wife's and if I'm driving someone else's.

 

How did you mount that in your car? I saw a post from a member named Pocket who cut and sectioned in an 8.8 to his stock third gen axle tubes. I was thinking of doing that with some other type rear axle housings, too, but I just am not sure at the end of the day it would be worth the effort for the result. I don't like breaking stuff AFTER I have repaired and modified it.

Who custom built your rear axle assembly? How much did it cost?

 

Member named "Cam-" built it.

 

Well, looks like option 1 is being pursued first. I now have an 02 Zexel Torsen posi with 3.42's, and a new 28 spline axle shaft HD setup from summit. I've got a solid pinion spacer to replace the crush sleeve. All of this is going into an 84 Trans Am housing with OEM Disk brakes.

Am I missing anything else to give this poor 7.5 every reasonable budget build advantage?

Let me know!

 

Any yet you included a Dana 60 in the choices. You'll lose more power and gain weight with a Dana 60 than you will with a 9". There's nothing wrong with a 9" and they can easily and cheaply be upgraded for even more strength. Mine is surviving quite well and I'm pushing around 1000 hp through it.

You'll never see the difference in power lost through the diffs unless you have it on a chassis dyno. Anything less than 10 HP difference will not be felt on the street.

I agree with ttop350's choices in order of preference. I pushed a beefed up 10 bolt into the low 11's or high 10's before swapping it out for a 9". I should have went with a 9" from the start and saved all the money I dumped into the 10 bolt. I put a transbrake in the car and knew the tiny 7.5" ring and pinion wouldn't last long.

 

Dont forget to get a diff cover with cap supports. theres a wild looking one on jegs that even has a extra hole to put a brace from the center section to the outer axle for strength. some say that fixes the weakest link in a 10 bolt by reducing the flex in the differential housing

 

good luck

 

i noticed the 1990 axle i salvaged 28 spline axles from
looked like it had revised and heavier external ribbing
around the pinion bearing area VS earlier axles i have
-kinda looks like this area was improved to reduce pinion
deflection in the later 3rd gen rears...
Also once had to change an axle on my early disk rear-
used a drum rear axle and had to turn the flange down
just a little as it was too big diameter to fit the disk-
may have to do the same for 28 spline axles in a pre-
'89 disc rear.Looking on 4th gen forums,appears the
torsen posi can be a little"brittle"under heavy abuse
-a few were seen where the area the carrier bearing
presses onto had snapped off,looks like the helical
tooth axle gears put a lot of outward force on the
carrier ends when subjected to high RPM clutch
sidesteps and the like

 

This is what I have on/in my 10 bolt upgrade along with 28 spline axles. I'm only pushing a 5.0,auto,DD so this works for me.
http://www.jegs.com/i/L.P.W./619/301-7.5G/10002/-1

 

ya that's the one. LPW's ULTIMATE-7.5 notice the extra holes on the outside where it says ultimate 7.5. that's where you mount braces(also sold at jegs) that connects to the end of the axle tubes.

Forgot to mention, welding the axle tube to the center section is another way to add strength.

 

Thanks for the extra suggestion guys, I really appreciate it!

As for the Dana 60, well, I have an emotional attachment to them. I used to use them when I was building 4x4 pickups out west and I just love them. I DO remember reading something about horsepower loss of the Ford 9" due to the placement of the pinion in relation to the center of the ring gear and the Dana being better. I don't remember where I read that but I am sure the magazine article is in a box in my attic somewhere. I'm sure its a negligible loss so no big deal. I appreciate the input.

For now the 7.5 will be run. My Firebird is being pressed into DD status before it got to get too disassembled for the engine upgrade. That should keep the horsepower nice and low and the danger away for now!

 

If you decide to use the L.P.W. cover it states in the directions not to use a gasket.Only RTV Silicone. That elevates even the tiny amount of compression from one side to another with a gasket.Sounds like overkill but is there really such a thing when working with a 10 bolt, and it also shows the tube braces. I just like to include this link because it shows how large and complete this Co. is and its made in the U.S.A. Heres a link to there site. = http://www.lpwracing.com/Ultimate_GM/Ultimate_GM.html
Obviously you must scroll down a little to see the 10 bolt.