I don't really understand the difference in all of these options and changes. What do I want to have... daily driver, I wouldn't mind dragging once in awhile. Tires aren't a huge deal. I have an 89 IROC, what does it have, and do I want to keep it. (I know it has a 2.73 rear end and I definately want to change that)
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Angelis83LT
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Apr 9, 2013
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- Car'83 Berli, '84 Berli, '84 Z28 HO
- EngineL69, LG4, L69
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- Axle/Gears3.08, 3.08, 3.73 Posi
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I am pretty sure all Irocs got the limited slip rear in them. Positrac and all that are all different names for the same thing. It is a good thing to have if you want to do any performance stuff... not really necesarry on a Daily Drive though.. but yours should have it.. easiest way to tell is if you have any gravel driveway or roads near by... take it.. stop it.. and then lay into it... if you end up with two dig strips you have posi. if you only have one. you have an open diff lol
sofakingdom
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IROCs most definitely DID NOT all get posi. Especially not the low-end ones with the 305 auto. Although with a TPI car the odds are better than the TBI ones, of which basically NONE got it.
Posi = short for "Positraction", a GM trade name for the generic term "limited slip" that they used back in the 60s; and it sort of stuck. Other trade names for the same thing over the years have includes Sure-Grip, Traction-Lock, Quadra Track, Smart Track, etc.
If your rear has drum brakes, don't bother upgrading it. Go find yourself a 90-92 disc rear out of one of these cars. Spend your money on that instead. The other is about like polishing a turd; you can maybe get it REAL shiny, but guess what it still is, after you get through. Get something better to polish.
Once you get a good core to work on, get a set of regular gears, NOT the Richmond drag-race ones; 3.42 is about as far as you want to go; and either an Eaton high-perf carrier, or a Zexel out of a 98-up (LS1) Z28 or Trans Am, like the ones SLP used to sell a long time ago. Since you'll be starting out with a 90-92 rear, it will have 28-spline axles, so you'll want a 28-spline carrier to match. I'd avoid the Auburn, as I personally have had consistently short life out of them (for reasons other than wearing out the clutches); others may disagree, but that's my $.02 worth.
Posi = short for "Positraction", a GM trade name for the generic term "limited slip" that they used back in the 60s; and it sort of stuck. Other trade names for the same thing over the years have includes Sure-Grip, Traction-Lock, Quadra Track, Smart Track, etc.
If your rear has drum brakes, don't bother upgrading it. Go find yourself a 90-92 disc rear out of one of these cars. Spend your money on that instead. The other is about like polishing a turd; you can maybe get it REAL shiny, but guess what it still is, after you get through. Get something better to polish.
Once you get a good core to work on, get a set of regular gears, NOT the Richmond drag-race ones; 3.42 is about as far as you want to go; and either an Eaton high-perf carrier, or a Zexel out of a 98-up (LS1) Z28 or Trans Am, like the ones SLP used to sell a long time ago. Since you'll be starting out with a 90-92 rear, it will have 28-spline axles, so you'll want a 28-spline carrier to match. I'd avoid the Auburn, as I personally have had consistently short life out of them (for reasons other than wearing out the clutches); others may disagree, but that's my $.02 worth.