Assuming I could only get one or the other done (if that), what should I work on? I have the stock tpi setup on my zz4, and also have 2.73 gears. Which would give me a better 1/4 time? What could the costs be? What exactly should I get? Lets say I have $500 to spend.

 

NOTHING WITH 2;73 YOU WOULD HAVE TO CHANGE THE CARRIER AND IT COSTS 800 CANADIAN

 

Hmmm...well, I know i can get the gears switched out for $500. A reputable place here in town does it for $500 total with the carrier I need and all. Also, I am guessing I can get some porting done for not much either?

 

You do need a new carrier, like an Aburn posi unit. That is about 300-400 (US$). Then you have to get the ring and pinion @ 150-200. Then new bearing etc.

I suggest to keep an eye on the local junkyards and pick up a 4th gen, 3:42 complete rear end w/ disk brakes.

There are pleanty of tech articles and post on how to do that.

I went from a 2.73 to an 9 bolt 3.23 which took me from a 17.1 to a 15.9. I'm just taking a risk w/ the 9-bolt cause it would be really expensive to fix if it broke. I'm currently searching for a 4th gen set-up

The 2.73 is for highway or more top end. A 3.42 is a good compromise and a 3.73 or 4.11 is not intended really for continuous long trips..... but we do have overdrives trannys, don't we.

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Michael Graeber

My Garage

1)83 Z-28 T-Top: Full cage, 9" w/ lad.bars, Midwest Engine Tech 406sbc,Strip Dominator, 1000-CFM Demon Carb, Phase VI Chevy Bowtie Heads 2.05/1.60, .630" Crower roller set-up, 1 3/4 coated Hookers 3" true dual exhaust th400, fuel cell & still not running

2)89 Formula WS-6 305 TPI Auto Daily Driver: minor motor mods, more suspension stuff. MODS

[This message has been edited by graebz28 (edited May 31, 2001).]

 

With the ZZ4 i'd say go with an upgraded intake. I have the Edelbrock Hi-Flow and SLP runners. Everything was cleaned up and matched. My car pulls way past 5000rpm and after getting my ignition problems fixed it seems to want to go all the way to 6 grand before shifting now! I'd say you will see better all around performance, i.e. driveability, mileage etc, than by fooling yourself into feeling you are going faster with lower gears. I have 3:23s but wish I had 3:42. Anything higher and I think traction would become a big problem. I liked the idea of getting a used 4th gen rear rather than paying $500 to upgrade your gears. Sure it's a little wider but 4thgen rims are a dime a dozen. And SLP is always running deals on take-offs.

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Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

I agree that you would want an auburn posi or even another good after market posi, but if you stock posi already works then you can just call summit and tell them that you want 3.73's or 3.42's that fit a 2 series carrier. I konw a few people that have done this and the gears are just thicker than the 3 series gears.


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*1989 RS
*Red, Daytona Turbo fiberglass hood, chrome 16x8 IROC wheels
*355 CID
*TPI ported plenum, SLp siamesed runners, Edelbrock high flow intake
*Edelbrock TES Headers (getting SLP 1 3/4 this summer)
*Richmond 3.73
Modded 700-R4, 2800 stall converter
NO recent time slips.

 

Get the intake stuff. You will brake the 10 bolt soon anyway.

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1991 Z28 ZZ4 with LPE superram base, SLP runners, LPE 58mm T-body,Random Technology ramair,TES headers,24#svo injectors,and just about every other bolt on that there is. Just got a ZEX nitrous kit!

 

go find aa 3.45 9 bolt the 9 bolts have a thicker and larger ring gear also if you ever brake a 10 bolt the axle most likely will shoot out the car if you are going fast enough the 9 bolts have bolt in axles and seem to take the abuse better i scored my 3.27 9 bolt from an 89 iroc(11in. brakes)for 350 and i have about 12-15 runs on it as well as daily driving duties with no problems that'll give you roughly 150 towards something else i.e(used slp runners).