2.73 replacement - what would you choose?
Thread Starter
Member
iTrader: (1)
Joined: Jul 2007
Posts: 174
Likes: 0
From: Kettering, Ohio
Car: 1988 Iroc convertible
Engine: 305TPI
Transmission: T-5, swapped it in.
Axle/Gears: no clue, but I'll learn
2.73 replacement - what would you choose?
Hey all,
I've got a 2.73 rear end on my 88 IROC vert, did a tranny swap to T-5. 305, but I think the engine was rebuilt, runs pretty strong for a 305. Not taking it to the track, just want quick around town, etc. Advice? What would you put in? Wouldn't mind rear disc brakes. Something posi, I assume? Thanks!
I've got a 2.73 rear end on my 88 IROC vert, did a tranny swap to T-5. 305, but I think the engine was rebuilt, runs pretty strong for a 305. Not taking it to the track, just want quick around town, etc. Advice? What would you put in? Wouldn't mind rear disc brakes. Something posi, I assume? Thanks!
Senior Member
iTrader: (3)
Joined: Oct 2004
Posts: 805
Likes: 3
From: Charleston, SC
Car: '85 TA
Engine: 350 turbo
Transmission: T56
Axle/Gears: 3.70 posi 9bolt
Re: 2.73 replacement - what would you choose?
You probably want to get a 3.42-3.73 9 or 10 bolt posi rear end. It will feel like another car.
Thread Starter
Member
iTrader: (1)
Joined: Jul 2007
Posts: 174
Likes: 0
From: Kettering, Ohio
Car: 1988 Iroc convertible
Engine: 305TPI
Transmission: T-5, swapped it in.
Axle/Gears: no clue, but I'll learn
Re: 2.73 replacement - what would you choose?
thanks zman. I took it to the local IT shop to try to get a speedo gear...they said the 2.73 was for a 4 cylinder. Told them it was standard for the automatic. Recommended a 3.73. My issue is with the 700R4, I was taching at like 2200 at 75mph or so. Since the T-5 it's more like 3K+. I thought with the 3.73 it would really be up there. I'd like to be able to drive to Cleveland, couple hundred miles without it thaching at 4K. Seems like I've seen lots with the 3.42. If I knew what I know now, I think I would I'd have done a T-56. Not really a gearhead (noob, I guess) so I'm learning as I go. But it is SO MUCH FUN with the stick. Plus with the headers, Flowmaster, it sounds great. Just want it perfect.
Senior Member
iTrader: (2)
Joined: Jul 2007
Posts: 777
Likes: 4
From: Tampa/New Hampshire
Car: 91 camaro RS, 87 T/A
Engine: 350 TBI, 305 TPI
Transmission: 700r4
Axle/Gears: 4th Gen 3.42/BW 3.45
Re: 2.73 replacement - what would you choose?
Get a set of 3.42"s or 3.45"s if you have a 9 bolt. Your better off swapping in a new rear end though, with disk brakes while your at it. Just go to your local JY and start popping diff covers off and counting ratios. I wouldnt go for 3.73"s though if your driving this thing daily, i think anything above 3.45" is overkill for a street car.
Supreme Member
Joined: Mar 2002
Posts: 1,176
Likes: 0
From: Springfield, MO
Car: 92 T/A VERT
Engine: LB9
Transmission: AUTO
Axle/Gears: 7.5 / 3.42's
Supreme Member
Joined: Jul 2006
Posts: 1,674
Likes: 3
From: Windsor Ontario
Car: 1987 Firebird Formula
Engine: 2004 LQ4
Transmission: T-5 WC
Axle/Gears: 3.42
Re: 2.73 replacement - what would you choose?
I just put a 3.27 in my TA project car, better off dropping the whole thing and starting from scratch..
Trending Topics
Thread Starter
Member
iTrader: (1)
Joined: Jul 2007
Posts: 174
Likes: 0
From: Kettering, Ohio
Car: 1988 Iroc convertible
Engine: 305TPI
Transmission: T-5, swapped it in.
Axle/Gears: no clue, but I'll learn
Re: 2.73 replacement - what would you choose?
someone offered to sell me a 3.27, 9 bolt, 4 pinion posi Borg Warner with disc brake brackets. I've got a 2.73. Would I notice a decent difference with that? What he's offering sounds good...
Re: 2.73 replacement - what would you choose?
In all honesty, I would stick with a 10 bolt rear. The 9 bolt rears are a bit stronger, but new replacement parts for them are virtually non-existent. You can get bearings, seals, etc., but there's no source for new posi carriers, and they're prone to burning out often. My suggestion would be a 10 bolt with either 3.23 or 3.42 gears. Either of those ratios work superb with the T5 on a street car, and they won't wind it up too high on the freeway. Btw, I was just up in your neck of the woods visiting my dad. He lives in Beavercreek.
Thread Starter
Member
iTrader: (1)
Joined: Jul 2007
Posts: 174
Likes: 0
From: Kettering, Ohio
Car: 1988 Iroc convertible
Engine: 305TPI
Transmission: T-5, swapped it in.
Axle/Gears: no clue, but I'll learn
Re: 2.73 replacement - what would you choose?
No way! Hope the weather was better than it is right now. Cold & snow flurries, windy. Thanks for the input Pat. I think it will be a 10 bolt, I'll see what I can find 3.23 or 3.42.
Re: 2.73 replacement - what would you choose?
Lol. As far as the weather went, I got there a few days after the hurricane winds and the massive power outage. Got there on a Sat., and we didn't get the power back on until the following Wed., so for those first 4 days we just sat around twittling our thumbs by candlelight!
The good news on your end is that there's quite a few guys around there that part out 3rd gens, so you shouldn't have too much trouble tracking down a good 10 bolt. I would've gone on a parts shopping spree while I was there if it wasn't so expensive to ship anything large all the way back here! I did manage to smuggle a gallon jug of that great apple cider from Young's dairy in my suitcase though.
Take care, Pat. P.S. Looked at the pics of your car in your vbgarage. Pretty sweet, lots of potential!
The good news on your end is that there's quite a few guys around there that part out 3rd gens, so you shouldn't have too much trouble tracking down a good 10 bolt. I would've gone on a parts shopping spree while I was there if it wasn't so expensive to ship anything large all the way back here! I did manage to smuggle a gallon jug of that great apple cider from Young's dairy in my suitcase though.
Take care, Pat. P.S. Looked at the pics of your car in your vbgarage. Pretty sweet, lots of potential! Last edited by Pat Hall; Nov 18, 2008 at 02:48 AM.
Member
Joined: Sep 2008
Posts: 240
Likes: 0
Car: 89 Formy
Engine: carbed 355ci
Transmission: A4
Axle/Gears: 3.73 10 Bolt
Re: 2.73 replacement - what would you choose?
crouchman..how much did the t5 swap cost you?...i went from 2.73 to 3.73
in an auto car...but is is the best thing ive done so far
in an auto car...but is is the best thing ive done so far
Thread
Thread Starter
Forum
Replies
Last Post
ElPaleterro85
Body
2
Aug 13, 2015 03:49 PM
knight72
Engine/Drivetrain/Suspension Wanted
0
Aug 10, 2015 09:32 PM




Go to a jy and pick up a 10 bolt. most are 3:42 posi. 