ransam

iTrader: (2)

I will be purchasing a new rear in the next couple months and im looking for any tips or suggestions before i order. Im leaning towards the s60 as of now. The car is an 88 trans am with a lq4, and th350 that is a street/strip car. I have the stock mesh wheels that i use as well as 15x8s with 275 60s for track duty. The car has the 9 bolt with disc brakes and i would like to keep to factory disc brakes for the new rear. Anyone that has ordered a new rear is there something that you wish you wouldve ordered but didnt or didnt think about? This is a big purchase and i want to do it right. Thanks for any advice.

Blackdog36

iTrader: (3)

I'm in the same boat as you although I am leaning towards a fabricated 9" with wavetrac. Your aftermarket choices are Dana S60, GM 12 bolt, Moser fabricated 9" (M 9) or Midwest Chassis Fabricated 9". Both of the 9" rear ends come with special torque arms so if you already have an aftermarket one, the S60 or 12 bolt may make more sense. I believe all the aftermarket rear ends will not accept stock 3rd gen drum or disc brakes. You will have to buy aftermarket ones or use 93-97 or 98-02 fourth gen mounting brackets. This adds to cost of converting the rear end. Both 9" rear ends are more favored due to ease of center swaps and part availability. Any of them would be strong enough for your build. From what I have been pricing out from websites, looks like S60 and 12 bolt would be a few hundred cheaper. Any of them add up quick with brake conversion and painting the unit!

Lastly, I'm still looking into is it worth it to narrow rear end from stock. From what I've researched looks like a 275 wide tire on a 15x8 rim is largest you can run before rubbing issues. I'm not sure if you can have a wider tire but that it will just stick out fast fender. Just looking to use a wider drag tire at track, not normal driving.

You will have to let us know what you get!

Night rider327

iTrader: (13)

The 9" rear ends do not come with a torque arm, nor do they need a special TQ arm.. They do need and come with a special torque arm rear mounting bracket/plate. Any torque arm will fit it.

I have a Moser 9" ford in my '88. I use a Jegster adj. TQ arm on mine.

You can fit a larger tire without tubbing, but why really. A MT 275/60-15 or 28 x 10.5, or 28 x 11 will hook with 600+ HP. Also what class are you running in? Most street classes have tire limits. Like 10.5" or 11.5" tire class.

I have seen MANY non tubbed third gens run 295/50-15 and 295/55-15 (28 x 12.5) tires. It's all about the wheel backspacing. You need a 15 x 10 wheel with 5", 5.5" or 6" backspacing.
You do have to roll the lip some, remove bump stops, and hammer a few places in the back inside of wheel well.

Night rider327

iTrader: (13)

Oh yeah to get to the OP questions.
You can not run your stock disc brakes on any aftermarket rear end but the 8.8" ford.

You have to upgrade to 4th gen disc, or run drum brakes.

I bought the Moser 9" housing and axle package and got my third member from Valley speed diff. on Ebay, used late second gen firebird drum brakes (ground out the opening in the sec. gen backing plates to fit the big ford housing ends), then used new sec. gen wheel cylinders and had to re-flare my brake lines with the sae double flare rather than the stock metric iso bubble flare.

Blackdog36

iTrader: (3)

Night Rider, thanks for the info. Must have not seen where you can use any torque arm for the M9. Will save me some since already have an aftermarket one. My power level won't be over 600 hp so a 275 tire will work for me as not looking to roll fender.

dellman83Z

iTrader: (9)

I have an S60 and love it. Cant use stock brakes with it either, I used ls1 brakes that I already had. Make sure you get a good driveshaft to go with it. No sense in having a strong rear end and a weak driveshaft. One other thing, make sure you get the right gear ratio for your needs. I made the mistake of getting 4.10's which is great on the street, but too much at the track. I run out of gear and have to shift into 5th at the end which hurt my times a bit. Wish I would have got 3.73's instead.

MoJoe

iTrader: (5)

Brakes - you will not be able to use your 9-bolt brakes on any other rear end. Specifically, the backing plates will not bolts up to anything else. Whether the calipers interchange with other backing plates, I do not know.

LS1 brakes are a popular upgrade. A full set via e-bay tops out in the $250 ballpark. These along with any 10-bolt brake setup will work on a 12 bolt. Maybe on the S60 too, check the axle builder's site, or give them a call.

9-inch - see what the site's spec out for brake options. Anytime LS1 factory brakes will work, then any 10/12 bolt brakes will work, too.

dellman83Z

iTrader: (9)

LS1 brakes work on a S60, just need to send the backing plates to Strange when they build it because they are integrated into the housing ends.

ransam

iTrader: (2)

I wanted to stay away from 4th gen brakes since my track wheels are 15x8 and rub 4th gen calipers. So i guess im going with drums wich mean i have to change dist. block. Im also debating 3.73s or 3.90s as far as gear. I have a new 3 inch steel driveshaft but i believe i will have to have it shortened if i go with the s60 but what about the 9 inch?

Night rider327

iTrader: (13)

No driveshaft mod (other than conversion U joint) for my Ford 9" swap.

I went with 3.89 gears and happy with them but mine in no longer a daily driver and it has an engine that needs the deeper gears

Blackdog36

iTrader: (3)

ransam, regarding stock LS1 rear brakes not fitting 15" rims - first time I've heard about that. Just did a quick search and seems that the LS1 caliper is too big. Hmm, I was going to get LS1 rear rear brakes and use 15x8 tires for when I go to drag strip. Will have to see what other type of disc brakes will work. I am going to buy LS1 front brake conversion and was looking to get LS1 brakes for the rear too.

dellman83Z

iTrader: (9)

I personally ran ls rear brakes on the factory 15x7 five spoke wheels. Dont ask why, its a long story on why but it was brief. Theres a wierd protrution thingy on the bottom side of the bracket that needs to be ground down to clear, but they did work. Very tight in there.