I know that this has been asked many times before, but I have an 87' camaro that I have thought about selling becuase I have had a 383 short block sitting for about 3yrs that I have wanted to put into a chevelle (that I dont own yet). I love my camaro, I had it for 12yrs now, and I'm seriously thinking about finishing the motor and doing what needs to be done to the camaro to put the motor in it.

If I put 30 spline axles, aftermarket carrier, and decent aftermarket gears in the factory 7.5" rear, do you think it will hold up to the occasional trip to the track on a set of slicks. The engine is a 383, 12cc dished pistons, est 10.2:1CR, DART pro 1 200cc heads with minor clean up work done, 246/251° hyd roller cam w/ .560" and 1.6 roller rockers, vic jr intake, 750cfm DP. Right now the the short block is assembled but everything else is in boxes. I would estimate that the motor will make no less than around 460-480hp and similar tq.

If I decied to go a head with this project then I will be getting a TH350 with around a 3500 stall, and I plan to use 4.10 or 4.30 rear gears.

I know that Strange and Moser make bolt in 12bolts, 9", and Dana 60's but at a hefty $3200.00+.

So do you think it would be worth it to go forth with this project and just rebuild the 7.5" with stronger parts?

 

Here's a thread that you may find interesting =
https://www.thirdgen.org/forums/tran...0-bolt-et.html
If you decide to build your differential from scratch/new parts than this is a list of what I have done to my 10 bolt may give you an idea of what can be involved.Some of these parts are necessary for the build and some can be changed to match your personal preference as in brand and style L.S.D./Locker.,etc.

1. 3.42 ring and pinion =$ 200.00
2. master bearing kit = $ 90.00
3. axle bearings and seals = $ 30.00
4. 28 spline Eaton posi. Unit = $ 500.00 ( highly recommended )
5. 28 spline axles = $250.00
6. installation/labor = $ 300.00
7. and if you want ,a LPW Ultimate support cover = $ 160.00 ( also highly recommended )
   Thats $1,530.00 counting the cover.

Here's a link to Eaton = http://www.eaton.com/EatonCom/Produc...iLSD/index.htm and here's a link to the LPW cover = http://www.jegs.com/i/L.P.W./619/301-7.5G/10002/-1

 

I haven't heard of 30 spline axles/carriers being available for these rears. In general, though, I'd say if the 28 spline axles aren't adequate, the rear will be eating gears long before that, anyway. This is because of case spread, which is resisted somewhat with a support cover, but not entirely. And the higher the gear ratio, the more the spread. 4.10's is stretching it as it is.

A beefed-up 7.625" 10-bolt will probably hold your power as long as you don't use a tranny brake. Mine has gone 11.95 @ 114 with slicks, and is a daily driver. However, a beefed-up 10-bolt couldn't stand up to a single launch with a manual tranny and sticky tires, and tranny brakes are almost as hard on stuff as manuals.

I think you should reconsider the real cost of the stronger rears. Beefing up a 10-bolt that later breaks will just put you behind in the purchase you'll have to make anyway for something stronger. At least, that's the lesson I learned from my time at the University of Experience.

 

No 30 spline axles for the 7.5 rear end. The 28 spline axles are good enough considering the weakness of the rest of the rear end. I wouldn't put any money into the 7.5 at your power level. Just save that money and put it into something stronger.

 

There's no cheap or easy way to may a 7.5" much stronger. The above posts pretty well list what needs to be done but no matter what you try to do, you'll still have those tiny teeth which will break off first.

About the cheapest upgrade is a 9" housing package. A direct bolt in housing plus axles for around $1000. You supply a center section and brakes. Center section can be found just about anywhere including a junkyard however I'd recommend finding one for 31 spline axles and to buy a housing package with 31 spline axles. I won't recommend 28 spline axles even for a street car.

Finding a junkyard center section may not be exactly what you want but it would be enough to get you on the road and you can always upgrade later as funds allow. 3.25 or 3.50 gears and an open carrier. If you're luck, you might find one with 4.10 gear and a posi out of something like a Bronco. Nice thing about a 9" is that there's no series of carrier. Find a posi with 2.50 gears and swap out the gears to 4.56 if you want and still use the same posi.

You can look around in a junkyard to find a good 31 spline posi then find another 9" that has a gear ratio you want and swap the gears. Don't forget though that the factory posi are not that great plus they do wear out so finding one in good condition may be hard.

I pushed a beefed up 10 bolt deep into the 10's but switched to a 9" when I installed a transbrake.

Run what you currently have. If you push it hard enough to break the diff, then decide if a few thousand dollars is cheap enough for a better diff.

 

The OP asked about beefing up the 10 bolt so I showed what I did with mine.Thats the most expensive way to go with a 10 bolt build. There are cheaper ways of doing it but I chose this. That work and parts was suggested by the shop that did the installation called “The Rear End Shop”that's all they do. Any way for what I'm running its the perfect combination. If I were to swap out my 5.0 for something much stronger than I would want to be able to take it to the track every once and a while. I would have saved more money and gone with a 9”.Thats not the case though. Its a street car,and a fun one to drive and that was the hole point of the 10 bolt build.All in all with the power you will be pushing Id go 9".

 

I wont be using a transbrake, but I may use a line lock set up (roll stop).

In looking up Currie, Moser, and Strange, I find that both Currie and Moser make bolt in 9" housings but their cost to your door without a 3rd member is around $1750-1900.00, I dont know how comfortable I would feel going to a junk yard and pulling a 30yr old 3rd member out of a truck to use in my car. I looked on a few different website and the best price for a decent aftermarket carrier was between $350-425.00, then another $250-300.00 for the set of gears and master intall kit. Then, I dont have any experiance with tearing down or rebuilding rearends so I would likely pay someone to do that portion- so likely another $200-300.00, but I'm pretty sure that I could install the rear with the help of some friends. So for a 9" rearend to be in the back of my car I'm looking at around $2800-2950.00. This does include the cost of rear drums but not any other cost associated with getting them to work.

VS

The 7.5" with axles 250.00, carrier 450.00, gears and master intall kit 300.00, housing gurdle/cover 150.00, labor 200-300.00, and I get to keep my stock brakes, for a total of about $1400.00.

About the idea of not doing anything to the 7.5" rear and just put it all together and push it till it breaks: I positive that a 383 with a 246/251° @ .050 cam will feel pretty soggy with the stock open diff and 2.72 gears that are currently in there, especially since I will be switching out the 700R4 for the TH350 which has taller 1st & 2nd gears.

To keep from spending much money, I do have a G80 "posi" carrier from an 80's IROC that supposedly had 3.23 gears. I bought it about 4yrs ago, I believe that since it was in a car with the 3.23 gears that it is suppose to be a 4 series carrier instead of a 3 series. I could just buy a cheap set of Summit 4.10's = 150.00, Summit rebuild kit = 80.00, and a Summit alm gurdle/cover = 150.00, I would still need to have it done so that would still be about 250.00 which would put me around $600-650.00.

If it's just a bad idea all together to even use the 7.5", and I'm forced to go with a "bolt in" 9" or 12 bolt that is pretty much going to run me about 3000+ almost no matter how you look at it, then I will likely just scrap the idea of even doing the camaro, and just go back to trying to sell it, in hopes to buy a 71-72' chevelle.

 

The 7.5 only has a 2 series and a 3 series differnetial. The 2 series runs from 3.08 to 2.14 and the 3 series runs from 3.23 to 4.56.

If you only run street tires on it then you could probably get away with using the 7.5, but sticky tires are probably going to kill it.

 

I guess the way I look at is: if I plan to fix up this camaro to put this engine in it then I know I will have about 1200.00 into the chassis and suspension just trying not to twist the uni-body and to get any traction. I'm looking at about 2500.00 for the complete transmission swap (including driveshaft), I've figured since these cars have a little issues with cooling that I would get an aftermarket alm radiator, use the stock elec fan (stock is around 2200CFM), external trans cooler, plus some othere odds and ends to get the coolant system up and going right, which together i've priced out to be about 400.00. Without writting everthing, I have priced out about how much it will cost me to get this car in a decent shape to accept this engine, which without any rearend work would be around $8000 (including the headers and exhaust done). You add an aftermarket rear onto this and I'm at around $11250.00

For that much money I know that I can find a running 71-72' chevelle in decent shape that is already set up for SBC and street/strip. All I would really need to do is finish the motor and put it in.

I've still got about $1000 left of odds and ends (gaskets, pushrods, bolts...) that needs to be bought in order for the engine to be complete.

I started the motor, while I was in the military and had the money, but I unexpetadly didn't get approved for my reenlistment (military downsizing, my MOS/rate/job was 180% maned). Since I have been going to school, and I am now done and working as a FF/Paramedic. So now I have a little money again to begin working on this project.

The 71'-72' chevelles are my favorite car, I know that I will someday build one. But at the same time, much like you all I still have a soft spot in my heart for the 3rd gen F-bodies.

What do you think would be the best idea?

 

Okay, thank you. That's what I was trying to say then.

I had planed on buying M/T drag radials 295/60R15

 

OP I've found a seller that's pretty popular with the 4th gen crowd who has a decent price on a 9" housing. No axles, brakes or 3rd member....but I think it's lower than what you were finding. I don't think they are a sponsor here, so I'll PM the address to you.

 

the 7.5 is not going to hold up to any good power. even with all the top name parts, I have tryed to get one to hold up to my old liginfelter 383, just under 480 hp. the ring & pinon just fall apart..with slicks.

 

Ok i was just reading up on some things and i found you guys talking about the 7.5 so i thought id share my input if you dont mind! I personally have to disagree that the 7.5 wont hold any power! I have a 1991 trans am with a sbc 357 i had dyno'd pushing 340hp to the rear wheels with 341 ftlb torque. You can call me extremely lucky if you want but i also have a stock t-5 in this car! I used this car ALL this past summer on weekend drag racing. I literally made over 230 1/8 mile passes on this car with no problems! With 2 weeks left in the season it finally happened, I blew the spider gears in the posi(4.10 gears as well) (only one side) so it still drove on the trailer! This was all on a stock clutch, flywheel you name it! It runs 7.80-7.85 all dayin the 1/8th. It does have the good umi torque arm and relocator that helped tremendously! I changed the posi out with one from a 1996 firebird and finished the season winning my championship for the year!

 

Also before anybody gets confused and says they didnt put a 350 in a t5 car, Yes i know! I have a .040 over 350 semi-dish piston motor in the car! Stock clutches dont last long!

 

Read my latest post! I think you will enjoy it!

 

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bump,bump,bump,bump,
You knocked,
What do you want ?

 

I've taken a look at a PM that someone sent me and still the cost of that with supplying your own brakes... once it's all done and you have it into the car you are still looking at $3000.

I've got some thinking to do. I guess it will be pointless to put the motor in there with the stock 7.5", so my options are to go forth with this car and to put another rearend in it or to just wait and buy a chevelle.

Not to mention I've just recently gotten some enticing offers for the car.

 

Find a 9-bolt 3.27/3.45 gear rear end from a 1985 through 1989 L98 or LB9 car and bolt it in and go. It will handle your power level and probably be bought off craigslist for around $300.00.

 

^^ so you are trying to tell me that a factory 9 bolt which is barely stronger than a factory 7.5" will hold up just fine to 470hp/480tq (which these are conservative estimates), with slicks and 3500rpm launches. I a bit skeptical

 

I've done it on the 7.5 on 26-10.50 slicks. 420hp. Call it luck if you want to but I made over 230 1/8 mile passes last year and finally blew a spider gear in the auburn posi. Launching at 3k

 

Over 1000 launches with my 6sp stick 406 car with 1.65 60 ft times and never broke anything in the rear. Broke driveshafts but not the rear end. Car is in my sig but the 355 has been replaced with a 406. Maybe I am getting lucky. I have been bracket racing in the street class and street driving this car for 20 years.

 

How do you know these 28 to 23 year old rears even have working posi units ?
Do you need a support covers or are the trash stock covers enough ?

 

Check the posi before you buy it, and all I have is the stock cover. I have changed the gears to 3.91 and shimmed the posi tighter then stock but for the most part the rear end I am running is all stock.

I know these rear ends are not bullet proof but I believe they will put up with more abuse then the 10 bolts and if something does break they are safer. The axles are held in from the axle end and will not come out if you snap one like a 10 bolt will.

My car has 450 to 500 HP and this rear end has lasted way longer then I ever expected.