i have the stock nine bolt rear in my 89 iroc-z ....i need to find a rearend that will bolt right in to the stock position....... my fastest quarter time is a 13.11 at 106.5 with 2.73 gears thats with a 1.8 60ft. any ideas on what rearend willbolt in to my stock positions that i can put 3.55--to--4.11 ratios ? i found a rear out of a 95-z28 for $300 will it fit? i need something stronger than my stock rear..... thanks for input



please email info to blazn189@yahoo.com

thanks

 

You have "THE" strongest rear end made for your car. The 4th gen rear ends will bolt in but will be 2" wider per side, the problem is that it's just a normal 10-bolt rear end that is weaker than the rear end you have.

There are gears available for your 9-bolt. You'll have to do some digging to find them and they are NOT cheap. Your only other option is to go to an aftermarket Ford 9" or 12 bolt rear end and be ready to spend between 2000$ and 3000$ for a complete rear end with center section, posi, gears, and brakes. You should be fine on your current rear end unless you want to run slicks or go much faster.

 

Not technically. The strongest factory rear would be the Dana 44. Parts are a lot easier to come by and dirt cheap compared to the 9 bolt stuff. They aren't super easy to find, but they are around.

 

i am running slicks ..m/t 26x10x15....ive made 5 passes so far with them ........1.8 60ft. im only able to stall out at 2500 ,.......any more and my car starts to roll...to much power... so what are my options? can i beef up my rear end that i have or can i just buy .....a different rear ...........if i just wanted to make my rearend stronger what would i need ?????? what year dana 44 will fit????? my 2.73 gears just wont let me go any faster

five passes at 13.1 at 105/106 same night
atleast i know the car is consistent!!!

 

Interesting. I'd heard of the Dana 44, but just hadn't heard much about it.

So how do you recognize 'em?? There are a few junkyards around here, might be worth my time to look for it if I knew what to look for...

Thanks!

 

The Dana 44 has a distinctive asymmetrical 10 bolt cover. They're uncommon enough that I wouldn't bother looking for it. You've almost just got to be lucky enough to have one fall in your lap.

 

The only cars that they were put in were the Firehawks, however it was available at the local GM parts dealer during the thirdgen run, and was a service replacement unit for the 9 bolt. I bought mine from someone on here. True they are not real common but I didn't have much problem finding one. They are not cheap though, just all the parts for them are. I paid $1200 for mine.

And just to make it clear, there's LOTS of Dana 44 rears out there, however most are in 4x4 trucks and WON'T work. If you are looking in parts yards it has to be one from a thirdgen.

 

the only rear ends that will bolt under these cars are oens from these cars

the dana44 was in alot of vehicles not only 4x4's but in some 2wd such as some of the late '60's and older GMC C-1500 trucks,

and then under the usual vehicles liek the jeeps and scouts and so on
ive owned a few over the years, one scout i had was a 77 and was the II and right hand drive and had the AMC 304 engine, we have a 77 CJ-7 out back right now it has dana axles under it, 3.54 ratio


good luck

 

The third gen bolt in Dana 44 came in the Firehawk but was also available from the GMPPC. It hasn't been available from GM for many years. Chances of finding one is very slim. The Dana 44's were installed as front diffs on many 4x4 but there's no way you could install one of those in a third gen.

When I had a 9 bolt, it was a factory 3.27 gear posi unit. I was using a very powerful 383 stroker through a TH350 and managed very high 11 second 1/4 mile passes at 117 mph.

I changed that out to a beefed up 7.5" 10 bolt to get a better gear ratio and got down into the low to mid 11's. When I installed a transmission with a transbrake I also upgraded to a 9" at the same time and never looked back.

Unfortunately because of the torque arm design of a third/fourth gen diff, there are no other diffs available except from other third gens and fourth gens. None of these are really considered strong performance diffs. Even if you do find a bolt in Dana 44 that doesn't need to be rebuilt, chances are it will cost about the same as buying a bolt in 9". If you're putting enough power to the wheels where a stronger diff is required, you'll have to spend the money to buy a bolt in 9" or 12 bolt.