hey guys
im new here and any help would be awsome. i bought a 89 iroc 5.7 bout 3 yrs ago with no motor trans. built a 350, 80 over 515 lift cam. 3500 stall. 350 trans w/shift kit.wasnt sure what to expect 1/4 wise but was disappointed to run a 15.15 had smaller stall at that time replaced and carb at same time. ran a 14.24. big diff. now my problem is my rear end. 9 bolt with 2.77. ive looked around found that 9 bolt.com but heard alot about him not getting back plus seems like lot of money.any ideas if other carriers will swap out with out changin anything else. i can get another 9 bolt with 3.08 for 75 bucks but then have to order gears if i want bigger ( i do) also can get a rear out of early 90s s10 next to nothin think he said 3.50 somthin gear will the carriers swap. any help i really would appreciate thanks

 

I'm pretty sure you need a 3.27 or higher carrier to upgrade to better gears in a 9 bolt. As you've noticed parts are hard to find and expensive. If you want cheap parts and service, consider swapping to a 10 bolt axle. If you need extra strength look into a 9 inch, 12 bolt, etc.

 

The S10 rear will be set up for leaf springs not coils & have no torque arm mount. Yes it could fit anyways...IF you did enough custom fab work to get it to. Not worth the trouble for S10 axle.

And none of the S19 axle parts will swap with your 9-bolt, so it is basically useless for you.

Now.....An .080 over bored 350??? Talk about THIN cylinder walls! Where in the world did he find .080 over pistons?!?!

 

thanks for the replys. im tryin to stay with the 9 bolt rear which its sounds like im guna have to spend the money.the carriers with the 308 is the bigger one? so i can just order the bigger gear? as for the 80 over i work in a machine shop where we build motors all day long so pistons arent really that hard for me to come by and yes THIN

 

wow not sure what happened i was typin and it dissapeared but anyway 80 over wasnt my first chose at all but it was the second block i came across that was 80 over so i said what the hell go for it . havent had any prob. did get it about 200 deg. once but it was like 98 out side

 

I want to say the 2.77 and 3.08 both use the low carrier. 3.27-up use the large carrier. Do a search to be sure. By the time you locate a 3-series 9 bolt carrier, and buy the carrier, and gears, you'll have more invested then you'd have tied up in a junkyard 4th gen rear (slightly longer, but bolts in). The 9 bolt is neat right up until you have one with 2.77 gears and iron calipers.

 

i look at that cause im not sure if 9 bolt.com said 3.08 and up or 3.27 was 3 series. so if i would go with 4th gen rear how would u off set the lenght just use the rims from 4th gen. what size would the ring and pinion be 7 1/2 or 7 5/8 or they the same been told two diff. storys on that cause i bought a real nice use 3.73 gear while back thats 5/8 and again i really appricate the feed back

 

If those are your 1/4 miles times for a 350 you have more problems the the 9-bolt 2:77 gears. Or learn how to drive at the strip.

 

Most of your questions about 10-bolts will be answered in the following link:

https://www.thirdgen.org/forums/tran...-10-bolts.html

Nine-bolt info:

https://www.thirdgen.org/forums/faq-...now-about.html

JamesC

 

you might be right ive only been racin 5 or 6 times. and if u think i have more problems than rear end what might b your info on what u think it might b. and what kind of times you have just wonderin really love hearin what kind of power everyone gets out of these and what i might have to look forward to.

 

I see 4th gen rear ends on Craigslist all the time. Several are out there right now for $150. Also: www.ringpinion.com

 

I see 4th gen rear ends on Craigslist all the time in my area. Several are out there right now for $150.

Also: www.ringpinion.com

 

I see 4th gen rear ends on Craigslist all the time in my area. Several are out there right now for $150.

Also: www.ringpinion.com

 

JamesC thanks for the links they helped alot . ill have to check out craigslist thanks. now i know for sure what i need or possible opt. i can do more lookin

 

Keep in mind, that a 4th gen rear end is almost 4" wider (2" per side) so your wheels will fit differently & the 92-97s have the same disc PBR brake calipers & same sized discs as a 89-92 3rd gen, so the brakes aren't really any upgrade. But the differential is an upgrade, which you could just put in your 3rd gen axle.

To get better brakes, get a 98-03 rear axle, but then you might have to re-plumb the brake lines, if you new one if from a 4-channel braked car.

LS1 (98-02) rear axles are a good upgrade, but there are things to watch out for.

 

thanks but if 4th gen is wider then how would my axles work. and also i have the 9 bolt which there bolt in axles. so does that mean 4th gen are bolt in? and they r 7 1/2 or 7 5/8

 

Keep the 9-bolt.

The LS1 axle is simply a wider version of the 3rd gen 10-bolt, with bigger discs & a better differential. And you can upgrade the brakes on your 9-bolt, so no reason to discard it.
C5/C6 brakes on a 9-bolt

 

k u have me confused. what r u suggesting i do keep the 9 and upgrade that or go with a 4th gen. but didnt answer my questions. u said i could use my axles in the 4th gen but there a wider rear. please explain more

 

Your confusing the term "axle" as a complete rear end, vs a complete rear unit.

The internal axle shafts are not interchangeable.


I was saying to just put C5/C6 brakes on the complete 9-bolt rear end, instead of swapping in the wider 4th gen complete rear end.

 

k but the reason im wanting to swap isnt for brakes it for gear purposes.

 

The bigger brakes are a side benefit.

9-bolt are stronger & less likely to break. And if an axle shaft DOES break? At least it'll stay under the car. As you already know, the 10-bolts aer held in with c-clips & can exit the car when they break. But if you need 9-bolt parts, they aren't as cheap.

You COULD get a 10-bolt & convert it with a c-clip eliminator kit, if you wanted to go that route. http://www.summitracing.com/parts/MSR-9200/

To sum it up....10-bolts are cheaper & easier to get parts for, but need work. Your wheels will sit out about 2" per side. Depending on what wheels your running, they could be out of the car & rubbing might be an issue.

 

the rubbing is what i was worried about on that deal. mayb u can answer the carrier question for me. i know i can look it up but u seem to b pretty helpful. i think it said on 9 bolt.com the 2.77 is a 2nd series and i believe 3.08 it the 3rd am i right cause i cant get a 9 bolt with 3.08 for 75 bucks then i could just order the gear i want cause i really like the strength and bolt in axles everyone talks about so id like to keep the 9 plus id have extra axles and what ever else i could use

 

Stephen is no doubt arguing the 9-bolt is stronger. That's one of those die-hard thirdgen rumors. Look around a bit and there are just as many people who have broken 9 bolts as have broken 10 bolts. If the 9 bolt is soooo much stronger then the 10 bolt, why did GM sell a bolt in Dana 44 over the counter while the 9 bolt was available? Why did SLP feel the Dana was a better choice then the 9 bolt? Why did GM go back to the 10 bolt in 91 and stop using the 9 bolt? The answer is because for the money the 10 bolt is a better choice, and in performance situations there are better options then the 9 bolt.

 

drew i know ive been reading a bunch of articale on both rears. im really confussed on which way i should go i like the idea of 10 bolts cause the availabilty but at same time i like the 9 bolt to cause it does sound pretty strong

 

FWIW I had a 3.45 posi 9 bolt with PBR discs laying in my storage unit for about 4 years. It was missing a tooth off the pinion gear (actually it wasn't missing, it sheered off the pinion and cut through the back cover before it finally settled in the bottom of the rear). When I started looking around I found that I wasn't the only one with a 9 bolt missing a tooth or two. The one I had broke behind a low output early 80's 305. I wouldn't consider a 9 bolt strong if a 140hp 305 with street tires can break one through a T5.

 

wow and then u cant just go down to the parts store and buy parts. that a really bad down fall

 

Yeah, we threw a drum brake 10 bolt in the car and turned it. It had been a really nice 305TPI 5spd 89 Formula, but all the cool parts were removed, and someone threw a LG4 out of a 83 or 84 into it. The broken 9 bolt was a handy piece to have around since it had PBR brakes, and a 3-series carrier, but the gears were too expensive to replace. I gave it to the guy that bought my 86 T/A since it had a 2.77 9 bolt.

 

nice i read somewhere ( and ive been looking around for a while ) that only 75 where built in 89 with this rear. and also read guys saying theyve spent the money on upgrades and r running slicks for few yrs with no problems. so r they really that bad or they just like everything else. eventually they all brake? but at least 10 or even 12 bolts u can get parts for. so i guess got some thinkin to do. and let me say thanks to all of u for ur input im still up in the air but u guys r helping me alot. hopefully as i learn more bout these cars i can help out to

 

9-bolts were standard equipment on ALL '87-'92 GTAs & '89 TTAs. Way more than just 75 in '89. TTAs alone would put the # at 1500 9-bolts in '89.

 

i think it was just talkin bout the irocs . at this point it kinda hard to remember what everything said. ive been threw so many websites tryin to find parts for it and what other options i had. couldve been talkin bout a certain bolt it put in a seat.but now when i find info that i WANT i right it down

 

one more question for tonight and i have to go to bed ( gotta work in morn.) if i do decide to go with a 4th gen how do i tell the diff between 3 and 4 channel. anything jump out at u from lookin at them

 

I too have done a lot of research on the 9 bolt and purchased one from ThirdgenRanch and I was very disappointed. On a series 3 carrier (I have a 3:27 gear Posi W/ PBR brakes) you need to check the distance from the small flat surface of the posi cone to the end of the case on both sides...If there is no gap between the end of the cone and case, the case and cones are worn out and needs to be replaced. This is very common with 9 bolts. BEWARE if you buy used. If you really want to do it right.....spend or save up and get a Ford 9" made for you car. You will not regret it. I read an article about one guy that said he had around $2K invested in a 9 bolt and wished he put the money on a Ford 9" instead.

 

The brake lines.....3-channel has the fluid t-block your used to seeing, like on a 3rd gen axle. A 4-channel will have dual fluid lines coming off it, so that they connect & are controlled separately.

 

Keep what you have and the problem is solved. Uness you want a Drag race car instead of a daily street driver. Then you have to spend money & labor.

 

cool guna start looking around for those rears. had problem with my rear, was only one wheel. ripped apart found cones where wore out machined them and shimmed up works like a dream just lacks . and if i wanted a drag car id spend the money on 9" the whole thing comes down to wanting it to run alittle faster.and im the kind of person that likes to build things instead of just goin out and buyin something already done