I have a 70 cutlass i was thinking of doing the gm 9" ford conversion rear end on since you can buy the new rear end ready for the ford 9" carrier. Can anyone give me some insight on this? The 9" carrier where the driveshaft hooks up looks quite a bit lower than gm? Does this cause a issue? Looking for all advice on this? It would cost me about twice the price for a 12 bolt conversion. Running a 496 stroker olds with turbo 400

 

Check out Strange Engineering.
Thay make a S60 rear that is stronger & cheaper than a new 12 bolt.
The 9" & S60 both need a shorter driveshaft.

 

Figured it would be shorter, do you know about any other issues it would causelike the driveshaft hookup being lower ?

 

I’m not knocking the Dana 60…but I can’t find one cheaper than a a Quick Performance 9” set up for an A body.

The Dana is about 20lbs heavier of unsprung weight…but I’ve heard they’re a bit more efficient.

But at your power levels you’re not in danger of breaking either of them.
You will definitely need to get a new driveshaft made either way.
Ive had a QP 9” with 3.90 gears and a spool for 17 years now. Never an issue.

 

I will check them out, thanks

 

Most 9" are 1350 joints, so this would be a good time to upgrade your driveshaft and front yoke.

As far as your concern for the pinion height: the pinion angle can be corrected with adjustable upper control arms. Seems like they should be there, already.

 

If the driveshaft is shorter than it definitely would. Anyone in particular for the upgrade?

 

I put a 9" in my Buick in place of the 8.5 10 bolt. The driveshaft was actually too short. I already had a Dennys shaft. Luckily i was able to source a yoke that was longer.

Joints can be had in whatever size you want.

Be careful with quick performance.. the base 9" package is a tinker toy. You have to upgrade everything to get a decent rear. Not that there is anything wrong with that, but the money adds up quick.

No issues with the pinion angle. My adjustable arms were able to get in check without issue.

 

Quick Performance is awesome. I ordered an aluminum pumpkin but they sent an iron. I called them and they had a replacement pumpkin and return label in my hands within a week. Unfortunate mistake that cost them a lot of money, but they jumped right on it and didn't even try to convince me to keep the iron. Even with the upgrades it's still very well priced.
For rear end strength, the important detail is tires/usage. If you put slicks on it and go to the track then yes, the strength of the rear is very important. Otherwise, the tires will break loose before anything else, giving you a lot of safety margin.

One note - some Chevy's use an offset rear end where the pinion is 1" offset towards the passenger side. This is how Quick builds their rears, and I didn't know that. Olds put theirs centered. It's not critical either way, but my exhaust is really close, so there's very little room now. Just tell whoever builds the rear to put the pinion centered.

Any builder will put stock brackets on there so it'll drop in place. Adjustable upper arms are a good idea.

I use Driveshaft Specialist in San Antonio. Fast work, always spot-on, good prices.

 

I should have mentioned mine is from quick performance as well. The customer service is great. Very fast shipping and they will throw in a shirt with a little coaxing..


Also I used drum brakes from an 80s f150. QP has drums drilled for 5x4.75 pattern. That was cheap- less than 150 for everything and I was able to use the e-brake cable.

 

Quick performance makes a very good rear end for the money in equal comparison to the same product others have for twice the money. Yes a base 9in is okay for street and light racing. However for $2700 you can make a rear that will take some serious abuse in an A body or G body.

 

My Quick Performance housing is the HD Ford housing with the top ears and bottom brackets correctly positioned for stock control arms. I do not want a spool and there are only two viable choices for a No-Spin Detroit Locker--9" or Dana 60. Especially with the aluminum center, the Ford is a lot lighter, but the shallower pinion angle of the Dana gives less HP drag. One good thing about the Ford is that the stronger components are virtually the same price as the lighter duty stuff. I got 35 spline axles to match the Locker, and the HD pro-mod type Pro gears with 35 spline pinion and choice of using 7/16" or 1/2" ring gear mounting holes. The housing came with the ends for stock GM A body brakes, although the center holes of the backing plates need to be enlarged with a carbide bur, etc. because the axle bearings are larger than stock. The stock hole is 2.87" and needs to be 3.15". I got a fairly long diff companion flange and the long tailshaft on the Jerico trans to minimize driveshaft length. Mark Williams offers a good deal on their Masterline 4" aluminum driveshaft with yoke, which I chose for strength and high critical speed. As noted in another post, most aftermarket stuff has standardized on 1350 U-joints and that is a good way to go instead of the Olds sized u-joints, or worse, the 1310 size Chevy joints.

 

Dennys can whittle you an aluminum shaft. Very nice work.
Coat it with WD40 if you go that route.
See the measuring instructions, fool proof.

 

^^^^^^^^^^^^^^.
I have a Strange S60 and love it so far. I was able to stop by Strange on a business trip and talk to them directly. Basically my setup is good for 1000HP, so that provides plenty of cushion for my heavy, manual transmission car. ( Yes i know HP is only one factor, its just how the engineer was explaining my cushion after he knew car details. )
Just a touch under 4K as built including disc brakes, so not cheap.
Edit for details: Wavetrack carrier, chrome moly pinion yoke,1350 u joint, adjustable lower control arm brackets, willwood disc brakes, 5/8 wheel studs, 35 spline axles with access holes.

 

Its really hard to beat the parts availability of 9" stuff. The stuff is everywhere.

One issue I do have with QP is they don't, or least didn't, offer an axle seal option. They want the bearing installed with RTV. I've never been able to keep it 100% dry back there.

 

Did you get an aluminum from there? I'm intrigued.

Fleet Pride is a national truck service chain. I've had several done there. Our local hero, A-1 Driveshaft, was bought out and moved to a Middleton & Meads, also truck service, in Baltimore. They've consistently been about $280 for 3in 083 wall with 1350 joints.

 

THAT my friend is 100% the truth!
Every time I take my rear wheels off I have to scoop out a lot of axle grease and road grime. Every spring, I check the level of my differential fluid.
It’s definitely a bit messy.

Like I said, QP built this rear 17 years ago when they were just starting out. But so far I’ve never had a problem with quick performance..
I run a 3890 lb. Car on the street with drag radials. I’ve made hundreds and hundreds of passes at the track. it’s gone as fast as 10.59 NA. My 60’s are mid 1.4’s.
With a better converter, I think this car could be high 10.40’s and the rear end would be the last thing that I worried about.

Before I added the ARB I broke the rear portion of my frame twice. But the rear end was never going to be a problem.

 

Yes sir. Aluminum. Super light.Worth its weight in gold. Ain't she purdy...

 

I got my rear from them in '23, I think. It has normal seals on the axles, but I'm using the Torino ends. Might be different with the small ford ends??

 

I believe I also have the big torino ends. I'll have to put a study out on it. The constant seapage pisses me off. I'm always nervous passing tech, and of course stopping from 120 with grease in the drums.

 

Another option is Speedway Motors. I've used a housing and axle package from them along with a complete center section and it's been just great.

 

I would get a different carrier than theirs but it looks pretty good