How much will a Ford 9" rear Hold ?

have a Ford 9" rear with 28 spine axles . I am just curious how my HP & torque they will hold . It's from a early Mustang so if I change the axles to 31 spline about how much is that going to cost ?
I am building a 429 to about 450 to 500 HP . Will have a 4 speed toploader and 4.88 gears . Going into a 50 Ford Gasser . If I go to a 31 spine will I be able to use everything else the rear comes with besides the axles ?
Thanks for the help and advise !

Jim

Jim you have 8" in the title and 9" in the description.

Thanks and I just fixed !

Jim

If you plan on only using this on the street w/o slicks then leave the 28 splines in it. If you are taking it to the track then it needs better axles. A spline change requires that the center section be revised to fit the axles. If you are changing use a Detroit Locker instead of clutch units. Also a lighter car will put less stress on the axles. If the car is heavy (4000 pounds) and run at the track you may want to consider 33 spline because the cost for 31 spline is the same. The manual trans is more stress as well over an automatic.
There is allot to consider here.

Dave

a stock case will crack around the pinion but a good daytona pinion support will help out

It will be driven with street slicks most of the time and better slicks at the track . I will drive to local car shows and things like that . There is also some good places around my house to check things out as well ! When I go to the track I will tow the car and use better slicks there . This is a poor mans build . Not sure what a Daytona pinion is or where to find one . More of a toy than a real serious drag car . I just want to have some fun . All the tracks close to me will be 1/8th mile but when I want a 1/4 mile I will drive about 1 to 3 hours depending on what track I decide to race at . Not sure about the size of a slick I will be using either yet . That I will have to just see what other are going to use and see what people think I should go with . I have plenty of time to gather the parts before I will need them .

Jim

a 4.88 with a stick car is pretty stout on the lanch it is going to shock the rear end pretty good it the tire hold. i would think that stock 28spline axles are not going to last if it hooks good . if it were my choice i would update the locker to 31 spline, new axles, daytona pinion support, and yoke. if your on a budget look thru the junk yards for axles replace the side gears in the posi but used a daytona pinion support

What is a Daytona support ?
I am going to use a 31 spine . I didn't get the rear since I will have to buy new axles i just as well just but the housing and go from there .
thanks !

Jim

A daytona pinion support has a larger pinion bearing on the back side .They originally came in the factory N case 9" differentials .And probably originated from running nascar in the 60s .An aftermarket 9" N case comes with this option .I would get an aftermarket N case with daytona pinion support 31 spline detroit locker and 31 spline axles .And whatever ring and pinion you prefer .If drags only a spool is the way to go .Doug

Doug , Thanks for the information on the Daytona support .
I did read that the "N" case was the best choice of 3 different cases but they didn't say what the difference really was besides a larger bearing .
I will be using the car on the street sometimes along with the drag track . I was just going to use a spool . I know what the difference between the different spools are . Mini , Locker and spool . I am not sure if a race spool will be all that bad on the street . Not going to be driving the car all the time on the street . Just when I get the itch for having some fun or a car show someplace close to home .

Jim

N case is made of better material - Nodular iron verse grey iron in the regular housings. I know some guys run spools on the street, but to me not a good idea. Makes parking a pain, and tight turns basically have to drag the outer tire around. Not to mention if you have to push the car, just hope you only have to go straight...

Besides all that puts a lot of strain on the axles.

For what you are doing a good N case, daytona pinion support, detroit locker, and good set of aftermarket 31 spline axles be the ticket. I'd also skip right to a set of 1350 u-joints and yokes for the driveshaft. Now if this is all to expensive only advice can give is put a weak clutch in it. Let the clutch take the hit and slip a bit. Of course will come at the life of the clutch, but when you have traction everything has to be built stout or leave something that will give.

Steve

Jim you really need a working differential .Like 466cj says spools are hard on axles .You know a spool has nothing in to allow the axles to turn independly They are no spiders gears to allow making turns .The outside wheel will turn more than the inside wheel whenever making a turn .That makes life hard for your axles .A detroit locker is one of the best differentials .There are others stay away from any clutch type differentials all they do is burn up from dragstrp action .Good luck to you Jim just passing on some of my experiences.Doug

You're on a budget (we all are). You've got a 9" with 28 spline axles. Run it!!!! You will find out what it will take or you can build a $2000 rear end and never really know whether or not that you needed it. If you did not already have what you have, then you might want to select beefier options. It costs the same to buy aftermarket 28 spline axles as 31, 28 spline TractionLoc as 31...Ford 9s had a good reputation long before there were 31 splines, Daytona pinion supports, and Strange axles. But, if you decide to build, don't forget to ditch the crush sleeve and shim the pinion bearings!!!!!!!!!

I let that rear go . I am going to buy a housing from a friend , then just get some new axels made . I will just look for a locker because I am going to be using on the street more than I was orginally thinking about . It comes down to how much trouble it will be to get tags for the car to use on the street . If I can get tags easily then I will build a 31 spline locker rear .
Now if I can get a decent deal on a C6 trans then I will sell my new Lakewood blowsheild and rebuilt 4 speed toploader close ratio trans to pay for a trans .
So now I am going to just start the rear from scratch ! I won't need the rear for a good year or so !
Just trying to think ahead !

Thanks for all the help and great advise !
Jim

Can find some good deals on Ebay for 9" stuff if you look a bit. A lot of Nascar hand me downs, most of it is really nice stuff. Just have to watch as some of it is special purpose, especially some of the Detroit locker versions.

Steve

Is your. Rearend narrowed. I got a 9"non NCase but the next strongest one down.with 4.30s and a spoll 33 splines
I need a alum strange one with a locker with 35 splines and a 3.50 gear.

currie sportman case is a good piece at $250 new they will hold 600hp look it up at jegs or summit im running one 5 years with good luck 480hp on motor and 150 hose

The aftermarket has caught up so well in volumn, options, and price that it is hardly cost effective to attempt to use OEM parts unless you are doing a numbers restoration. Unless you inherit a drag pack pig, you might as well build from scratch with new parts or just order one up. Very little difference is money.

If you plan on drag racing anything with a 4-speed and slicks be prepared to break parts. Beleive me if your ride can hook the weakest link will bite you and take everything with it. Best thing to do is save your money,buy all the good parts.I wasted alot of money and time on resplined 31 sp axles, trac lok units as when they broke they took housings, gears ,yokes and driveshafts with them. Running an automatic (wo/ transbrake) is much easier on the drivetrain and a stock housing w/ a good pinion support, a detroit locker and aftermarket 31 spline axles can live behind a 550hp 3600 lb car w/ slicks running low 11's w/ 1.55-1.57 60's

I can say this my 83 gtstang. Has a 8.8 but has Ford teaching lock with 31splines only still with 4 lugs.mower axles 3.73 gears I tun a 408w with a TKOTrans.my best run was a 10.09. @138 MPH with 1.44 60 ft. Time.on Hoosiers dot quick Porsche 27x11.50x15 no rear end brakave so far. I launch at 4500 rpms and leaving on the nitrous.yes a have gone through a center force gold in 6 passes.I got a pro motion set up now.good for 850hp.haven't run it since 2005.
good luck to you sounds like a sweet ride