I have a posi borg warner rear with 2.77 gears. looking to upgrade to 3.73's but i cant seem to find anything avaliable for them.... summits tech line told me that they dont make aftermarket parts for it. uhh curious about what to do.... rebuilt the 10 bolt single legger and put a posi unit it it or continue searching....

Welcome to TGO. Maybe you can find something in the following link that will be useful (the 9-bolt seems desirable because it's a bit stronger; however, finding parts for it, as you've discovered, will be difficult):

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

FYI, the search function on this site will provide a ton of info.

JamesC

thank you and thank you for the welcoming. the link helped alot...

you will need a whole new carrier
for 3.70 gears

With a 2.77 9-bolt you're basically out of luck. Your best bet would be to replace the whole rear end with another 9-bolt with the gears you want, or swap in a later year 10-bolt.

have you ever rebuild a 9 bolt??????????
or any rear end for that matter????

Don't think the concern is with the work or know-how involved, but finding the right parts and the cost of those parts. I took the BW airplane geared rear out of my 88 and put in a standard 10 bolt for about 1/3 or less the cost of regearing the 9 bolt. If originality is a concern then of course the 9 bolt would be the way to go.

see my BW 9 bolt is basically brand new.... and its not the original rear out of my 85 Z. it was out of a wrecked 88 iroc that my uncle bought for parts for his 87, he sold the 87 and i ended up buying an 85 with a single legger so he sold me the rear.

thats how i ended up with the BW 9 bolt.

i just got my hands on a 10 bolt out of a wrecked 93 z.... helps when your uncle has friends who own junkyards.

but as for rebuilding the bw i would rather take a 10 bolt and have to build it 3 times then have to build a BW twice.... the price for those things is rediculous

no not anymore!!!!!!!

3.7 gearset=$165
if needed=motive gear=good stuff

re bearing set around $170
does not include axle bearings and seals add 45-50 bucks

a diff cover for loading the bearing caps=$170 if you absolutely need it

now if you re use the ring and pinion and dont get the fancy cover
its not that expensive is it
definately close to a 10 bolt in price
and stronger by far
----------
i forgot to rebuild the posi
machine the cones
or buy new for $177

i can help find the prices

see with rebuilding the BW 9 bolt its going to be another $555 which i dont have. im on a budget with this car. and the 10 bolt was 50 bucks.

i got my 3.45's off craigs list. Give it a go. Or post in the parts wanted TGO section.

Where can I find a bearing kit for my BW 9 bolt?

I think some of you guys are missing the point that you need a new carrier for 3 series gears, which, as far as I know, are not available easily (maybe still in australia?). he would be forced to find a used one to change ratios. the gears, and rebuild parts are readily available.

unfortunately, you're best bet would be to find a whole rear, or rebuild the 10 bolt, unless you are really lukcy and find someone selling a 3 series carrier.

i didnt miss the point can get posi units and or open carriers and spool etc from 9 bolt.com

that dudes prices are nuts... hahah yeah that 93 10 bolt fell through wasnt a posi. but my cousin has out he took out of a 85 iroc thats a posi so im trying to buy that one from him. either way i still have to return my gears because i got them for a series 2.

This is also a good source for 9 bolt carriers and axles, brand new heavy duty carrier with new Timken carrier bearings installed $450 US, but the shipping is not cheap. Same for 9bolt.com, all his parts are coming from Australia and shipping by sea mail, this adds about $150 to the carrier, I know first hand. I got a new carrier and 31 splined axles from the link below and the guys were very friendly and knowledable. Just BEWARE the posi cones he shows WILL NOT fit the GM production carrier, only the newer style Dana replacement carrier,like the one for sale below.

http://cgi.ebay.com.au/Borgwarner-He...742.m153.l1262

yeah ill stick with the gm 10 bolt..... ill look for a 7.5 rear with a 3.23 carrier so i can drop my gears right into it. cheapest and easiest way to go for my self @ this time.

hey, thats a cool link!

so you upgraded the axles to 31 spline? which ones did you use?

I actually don't know which ones, I measured each axle and sent the measurements to him. They were about $650/pair, but look twice as strong as stock. By looking at the pics I would say there the same as the Holden VL Turbo 31 splined axles, but I would talk to them first. It's not fun or cheap to receive the wrong parts from Australia.

yeah.... im pissed that i have to send my gears back to summit in ohio from CT. thats gonna be like 50 bucks.... hahah i can immagine back to australia.