Hello all. I am wondering outta curiosity what the best posi rear end choice would be for me and my z28. (See sig for engine size and what not.) I would like to go after a good posi soon. This car is also a daily driver though, so I don't want something specifically for race applications. I want something good and quick on take off, but not so crazy. You know what I mean. I aint digging my differential when I try to burn out. It's a one-tire-fryer. Sometimes on occasion I can get both wheels broke loose, but that's if I stratigically place my drivers side tire on gravel, or a wet spot on the pavement. Also, what kind of prices can I expect for rear ends suggested? Thanks.

 

3.73's are always a good choice

But you might even be able to run 3.42's on that 305.

 

It all depends on whats under the car now, then you can check your choices for a upgrade. Such as New Gears & Limited Slip or a Rear Axle swap with rear discs. Now you are .

 

Nope, no further questions your honor. Thanks guys.

 

I have 3:23s and I like them, But 3:42`s would be a better choice

 

Opps, I never mentioned this. It's a 700r4 tranny.

 

First you have to figure out what rear end you have, if it's a 9 bolt or 10 bolt and then you need to make sure of your axle spline count, if it's stock, it should be 26 splines, but best to make sure before you order stuff.

If you have a 10 bolt, I'd go with an Auburn Posi and 3.73 gears with your setup.
Most likely you have a 10 bolt, if you do have the 9 bolt, parts are pricey for it, gears are about $300, vs $150 for 10 bolt gears.

My 9 bolt with a worn out posi would spin one wheel sometimes, but most of the time it would spin both.

 

With your 305 any posi. unit will work fine, including stock. I think you'ld be better off buying the complete use rear end. It's much easier to swap as you don't have to mess with all the gear setup. It's probably cheaper too.

 

Well, I assumed it was a posi rear end, till I had it on a lift and spun one tire and the other went the opposite direction. 3.73's is what I hear are cool too. I think I'll look into those. Thanks.

I hope I got the 10 bolt. I'll write back later when I figure it out.

 

From what info you supplied, my guess is you have a LG4 engine with a Auto 700R4 and 3:08 non-limited slip rear using 26 spline axle shafts.

If I am correct, all your choices are limited and are expensive. So if I were you, I would rethink this project on the small performance gains made with your cars other components. Just my opinion.

 

Well, heres the thing. When I land a good job, I want to go after a bigger engine, but I need to know this info, and I could probably get the rear end soon, and already have it in. I just can't afford the big stuff yet. I just got this car 3 weeks ago, and want to make it quick, but not for drag racing. I would settle for a 305 tpi, or 350 tpi. That's what I really want to do.

 

the 3.42 could be on his car already, but not the posi unit. My old 84 Z28 (L69) had the factory non-posi 3.42 rear.

 

i have the factory non-posi 2.4-sumthin gears and i was quoted 1100 bucks by a speed shop cuz i needed a new housing and stuff like that. so i agree with 87DJP2001 when he says its gonna be expensive, but it will help your top end speed (right?). my car pulls hard through first and second but it takes forever to get through third and with my 110 restrictor i don't even think it hits 4th...

 

id say your factory unit with 3:73's and a good posi setup will really help get that car out of the hole