1987IROC350

The only gears offered for years to us were 3.70's for the 9 Bolt BW (7.75").

The factory gears for 350 TPI cars were 3.27 for '87. All other years had 2.77 with 3.27 as an option.

Ringpinion.com now offers 3.73 and 3.45.

Just wanted to let ya'll know in case you want some more get up and go

http://www.ringpinion.com/PartCats.a...ffName=GM+7.75

sn8ke eatr

wish i knew this when i had a 3rd gen

quickchicken

from the looks of it they are getting their stuff stright from Austrailia. i priced the stuff once and thats about the cost from there. the carrier price looks like what it cost new from GM when they were still avail from GM.

Stephen 87 IROC

3.45 was also a production option.

www.9bolt.com has offered many other ratios for a long time and they all come from Australia.

If your car has 2.77 gears, it's on a 2 series carrier. To upgrade to any of the deeper gears, you'll need a 3 series carrier.

rickyzZ28

Exactly what I was going to say, I ordered from them like 5-6 years ago for my carrier, 3.73 and install kit. After all this time everything is still great, but they have always been a little noisy, but I have had them looked at by 2 different places just to make sure I put them in right and both said they look great and I am running them with MT ET streets and a nitroused 355 LT1.

1987IROC350

Yea 3.45 BW was available but only with the 305 5-speed TPI cars from '88 on. Not the L98. I wish I had it from the factory.

Thanks for posting the 9 bolt.com. I had forgotten about them. I might get the 4.11's. I noticed the site says all gears are used but not raced. I wonder what the chances of getting 4.11's that were for going to Church only on Sunday's

ayers1967

I don't want to hijack this post but . Is the 9 bolt and the 10 bolt rear end the same width? Also is the 9 bolt the only one that is 4 wheel disc.

quickchicken

the 9 and 10 bolt third gen rears are the same width and they both came with disk. the 89 year 10 and 9 bolts got the upgraded PBR calipers that is half of the 1LE system.

Racer001

I just ordered a set of 4.11s form 9bolt.com with a master install kit. Great price, great service! Came to $550 shipped for everything. Customs held my box for 5 WEEKS though

Then I found a guy in Ohio selling his 4.11 gears. I'm buying them too just in case.

ayers1967

Thanks for the info , I want to convert my 86 Iroc to 4 wheel disc.

quickchicken

2 tips, you must find 9 bolt brake plates and get the 89 model year plates, this will let you use the PBR calipers. 9 bolt and 1 bolt plates are diff. contact Ed miller over at TGO in the brake forums, he can help ya get the right plates.
also you will need the prop valve that goes with those calipers. the plus side is if you find the 1LE fronts later your set to bolt on, bleed and drive.

ayers1967

Thanks again .

jaykar

May be mistaken, but from going to 9Bolt.coms
website all the gearsets I saw there were used.

Don't mind used in good shape but would rather buy
new

Later

Racer001

new gears aint gonna happen unless you get aftermarket 3.73s from randys ring and pinion. The used 4.11 gears I got from 9bolt.com are in great shape!

jaykar

3.73 my choice anyway as sold the ET Street Drag
Radials, New, and went with BFG 255s.
Not race car but going from 3.27 to 3.73s and street
tires does ease the shock.

Broken well setup 12 bolts in the past with the power
I have now.

Thanks for info on Gear vendors for the 7.75.

Later