'85 Trans Am w/ an '02 Z28 10-bolt?
05-09-2007, 03:35 PM
#1
Question - 02 Z28 10-bolt in a third gen? Hi guys,
I was just wondering if anyone happens to know if this will work.
My brother has a 1985 Trans Am 5-speed with 3.23 gears I believe (stock) and I have a 1988 Formula Auto with the stock rear (2.73 gears with no posi).
I just bought a 12-bolt for my 2002 Z28, so I now have two 10-bolts sitting in my garage, one with 3.42 gears and one with 3.73 gears. If it will work, I would like to put one of them (3.73 gears) in his Trans Am and then put the 3.42 rear in my Formula.
Does anyone know if the swap would work or what that swap might entail? Thanks.
PS - I know the 10-bolts are weak, hence the 12-bolt for my LS1, but I don't know much about the reliability or strength of the stock rears in our third gens. Any info would be appreciated!
I was just wondering if anyone happens to know if this will work.
My brother has a 1985 Trans Am 5-speed with 3.23 gears I believe (stock) and I have a 1988 Formula Auto with the stock rear (2.73 gears with no posi).
I just bought a 12-bolt for my 2002 Z28, so I now have two 10-bolts sitting in my garage, one with 3.42 gears and one with 3.73 gears. If it will work, I would like to put one of them (3.73 gears) in his Trans Am and then put the 3.42 rear in my Formula.
Does anyone know if the swap would work or what that swap might entail? Thanks.
PS - I know the 10-bolts are weak, hence the 12-bolt for my LS1, but I don't know much about the reliability or strength of the stock rears in our third gens. Any info would be appreciated!
Last edited by PewterScreaminMach; 05-09-2007 at 07:53 PM.
05-09-2007, 10:20 PM
#2
It will bolt right in. I have an 02 TA rear in my 85 Z28.
The 4th gen rear is wider. The stock 3rd gen wheels will stick out past the quarter panels. Most people put 4th gen wheels on their car, and run spacers in the front. What brakes will be used? 4 channel or 3 channel rear?
The 4th gen rear is wider. The stock 3rd gen wheels will stick out past the quarter panels. Most people put 4th gen wheels on their car, and run spacers in the front. What brakes will be used? 4 channel or 3 channel rear?
05-09-2007, 11:16 PM
#3
Third and fourth gens aren't really any different strength-wise, they both suck. Both of your guys third gens have the older 26 spline / 7.5" combo vs. the 28 spline / 7.625" rears that all mid '89-up cars got. As stated above, the 4th gen rears are somewhere around 3 5/8 to 3 3/4 wider than your stock rear end and will kick the tires out somewhere around 1 5/8" each side. If using 245/50R16s the tires should be about even with the outer edge of the wheel wells.
I had a couple different LS1 rears in my '88.
I had a couple different LS1 rears in my '88.
05-10-2007, 01:23 PM
#4
Thanks for the info guys. It sounds like 4th gen wheels is the way to go if I do this.
I bevieve one rear is 3-channel and one is 4-channel. I don't think either third gen has ABS and I know they obviously don't have traction control, so will that be a problem with the 4-channel? I'm gonna have to check drum/disc breaks on both cars, but they are both stock in those terms, if that helps.
Also, I have read that there is a problem with the e-brake cables not working with the LS1 rear. Supposedly, this guy on thirdgen.org is working on a solution with some wiring company, but did you guys have a solution to this problem? How did you deal with it?
I bevieve one rear is 3-channel and one is 4-channel. I don't think either third gen has ABS and I know they obviously don't have traction control, so will that be a problem with the 4-channel? I'm gonna have to check drum/disc breaks on both cars, but they are both stock in those terms, if that helps.
Also, I have read that there is a problem with the e-brake cables not working with the LS1 rear. Supposedly, this guy on thirdgen.org is working on a solution with some wiring company, but did you guys have a solution to this problem? How did you deal with it?
05-10-2007, 01:28 PM
#5
By the way, DuronClocker, that is some crazy lift on your cam for such a short duration and a very low LSA. How is that cam working out for you with all of those supporting mods, heads, and 90/90 setup? Any dyno or track numbers with or without the nitrous?
05-10-2007, 04:45 PM
#7
Right, 3rd gens may never have had ABS or TCS, but when swapping rears it makes a difference.
You cannot reuse the 3rd gen rear axle brake lines as they are not long enough. Therefore you must use the longer 4th gen lines. 3 channel rears are setup just like the 3rd gens, with one source line and a splitter. 4 channel brake lines CANNOT be used as they require 2 rear brake lines.
I never dealt with the LS1 rear brake issue. Although I have an LS1 rear in my 3rd gen, I put LT1 rear brakes on - for several reasons.
You cannot reuse the 3rd gen rear axle brake lines as they are not long enough. Therefore you must use the longer 4th gen lines. 3 channel rears are setup just like the 3rd gens, with one source line and a splitter. 4 channel brake lines CANNOT be used as they require 2 rear brake lines.
I never dealt with the LS1 rear brake issue. Although I have an LS1 rear in my 3rd gen, I put LT1 rear brakes on - for several reasons.
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05-11-2007, 11:26 PM
#8
When I had my car, I had never gotten around to making the E-brake work (automatic, so I didn't feel the need). I understood there was a cable that should have been able to work and could be bought from a parts store.
The problem isn't just with a 4th gen rear. Its using the LS1 disc brakes. If you're going to run LT1 rear brakes or the stock thirdgen brakes on the 4th gen rear, you can get the right cables. They just don't make cables the right length with the right ends on them to fit the LS1 e-brake and the thirdgen e-brake adjuster on the car.
A 4-channel ABS/TCS rear can be used without a problem in a third gen, but you have to buy your own brake lines and bend them to fit and use the stock brake line T off your old rear. Very easy, I did it on my car when I first put the first of the two 4th gen rears I'd used.
Also, I'm using the "Patrick G" cam which utilizes LSK lobes 421rwhp/400rwtq (340-350 @ 3000rpms) through the 10-bolt and LS6 intake. Ran a 12.3@118 on bald Nittos and a terrible 60' time. Going to the track tomorrow for the first time with the ET Streets, 9", FAST90, SFCs. Looking for some 11.40-11.60s if the car's running right and my driving is on! I'm not sure how confident I am in it right now with how its running, but we'll see. Haven't sprayed the car yet. Still want to get a few more parts, and I'm not going to install the bottle til I re-do the interior soon.
The problem isn't just with a 4th gen rear. Its using the LS1 disc brakes. If you're going to run LT1 rear brakes or the stock thirdgen brakes on the 4th gen rear, you can get the right cables. They just don't make cables the right length with the right ends on them to fit the LS1 e-brake and the thirdgen e-brake adjuster on the car.
A 4-channel ABS/TCS rear can be used without a problem in a third gen, but you have to buy your own brake lines and bend them to fit and use the stock brake line T off your old rear. Very easy, I did it on my car when I first put the first of the two 4th gen rears I'd used.
Also, I'm using the "Patrick G" cam which utilizes LSK lobes
421rwhp/400rwtq (340-350 @ 3000rpms) through the 10-bolt and LS6 intake. Ran a 12.3@118 on bald Nittos and a terrible 60' time. Going to the track tomorrow for the first time with the ET Streets, 9", FAST90, SFCs. Looking for some 11.40-11.60s if the car's running right and my driving is on! I'm not sure how confident I am in it right now with how its running, but we'll see. Haven't sprayed the car yet. Still want to get a few more parts, and I'm not going to install the bottle til I re-do the interior soon. 