rearend question...

[noneed4nos]

Ok so i have noticed that alot of people put 9 in ford rears in the gn's. Now what is the advantage of this, is it stronger as well as posi? and what year/car out of should you look for, to put in my gn? Thanks guys

 

[charlief1]

Dirt track cars have been using them for years. Stronger housing and many more options as far as posi. If you decide to go this way get one of the housings from a dirt track supplier and it will fit better than one of the drag supplier. They really do know how it fits and make a much better unit.

 

[noneed4nos]

where would i find a dirt track one? anyone where in particular? Thanks

 

[charlief1]

where would i find a dirt track one? anyone where in particular? Thanks

smiliesracing.com, Speedway.com are two of the biggest but you need to get on some of the dirt track forums to see what works best.:biggrin:

 

[jevans]

With the 9" rearend, you'll never have to second guess if it will hold up with the horsepower levels we're using. The front loading 3rd member makes a gear change a breeze also. If you decide to go the 9" route, I would look into buying a direct bolt-in housing. It will make the install alot easier, all the brackets are already there, in the correct place...

 

[noneed4nos]

Where would i find something like that to fit direct?

 

[jevans]

Where would i find something like that to fit direct?

I have a Moser M9 Housing in mine, it bolted in and works really well. I know Currie Enterprises sell them also. I would say there's probably quite a few companies making them, seems to be a popular upgrade...John

 

[just plain john]

Currie Enterprises is a good place to start. Moser makes one too, but I've read some posts at another site that indicates fitment problems. Google it. In reality gear changes are rarely made once the rear is in the car, the 9" is heavier and has a greater frictional loss. Lots of people have gone fast with the stock rear, with some opting for an axle upgrade. I priced out a 9" prior to swapping out my rear and it was in the $2k range. I ended up with the 8.5 I gave $850 for, then put new bearings and seals in just for good measure.

 

[noneed4nos]

I just want to get into the low 10's and still be a street car as well, I have a posi 8.5 now, with that hold? I just want a good rear to have no problems with, Should i just freshen up my rear now or go with 9'?

 

[ttypewe4jim]

They might have corrected it but I know with some of the 9 inch "bolt in" rears............... they move the rear upper controll arm location up higher which can screw up the instant center.

 

[just plain john]

Low 10's are attainable with the 8.5. If it were me, I'd stick with it and use the $2k elsewhere. Of course, a 9" is probably the ultimate rear strenght wise, but not necessary for 10's.

 

[WHN378]

Ford 9"vs 8.5 10 bolt

Here is a link to Curries Currie Enterprises Rear End Sample GM A and G Body

I have been thinking about this for a while. Just don't have the money. Nothing you find in any ford will bolt right in. Like it has been said you need all of the stock mounting brackets.

DTS drive train specialist have a housing advertised in most car magazines and there are many others. The housings are not so expensive but the you need brakes, axles, and the third member. Maybe around $2500. by the time you get done.

I have gone eleven - teens with my stock 8.5 ten bolt from a 442. I don't use a trans brake and only 9" tires. 45- 50 passes so far.

The problem is when you get into the tens and get near 125 mph you are supposed to have "C" clip eliminators. The metric 8.5 rears like the buick and olds G-bodies don't really have a bolt up flange for the c-clip eliminators. Some people cut the flanges off and weld on ford flange ends.

I thought of buying aftermarket axles for the 8.5 ten bolt but I am still stuck with the c-clip. If money were no object I would do the 9". I have seen too many videos of people losing axles at the drag strip.

What to do ?

 

[just plain john]

Hmmm, I see they don't quote a price on the 9". Detroit locker, Wilwood disc brakes, 35 spline axles. Run your 8.5 and when it grenades, get another one just like it and STILL be money ahead.