I wanted some opinions on what I should do here:
I just found a deal ($125) on a rear end from a 87 Iroc, 2:73 geared Posi. The problem is that the housing is a little beat up, such as a cover bolt sheared off, and one of the bolt holes for the panhard bar has been torn (I don't know how). I had originally planned on having the 87 rear rebuilt while I kept my original non-posi rear in the car, for less down-time, but I'm concerned with the condition of the housing on the 87 rear. Could it be possible, and/or a good idea to have the carrier and axles from the 87 put into the 91 housing when I have it rebuilt? It'll kill my ideas about down time, but I know that the rear I have in the car right now is in good shape. Or would I be better off just ditching the 87 rear, and trying, again, to find a deal on another posi rear? I was also thinking I could get moser axles for the 87 carrier, and pop them into the 91, but cost is an issue or I would have bought an SLP posi carrier.
I just found a deal ($125) on a rear end from a 87 Iroc, 2:73 geared Posi. The problem is that the housing is a little beat up, such as a cover bolt sheared off, and one of the bolt holes for the panhard bar has been torn (I don't know how). I had originally planned on having the 87 rear rebuilt while I kept my original non-posi rear in the car, for less down-time, but I'm concerned with the condition of the housing on the 87 rear. Could it be possible, and/or a good idea to have the carrier and axles from the 87 put into the 91 housing when I have it rebuilt? It'll kill my ideas about down time, but I know that the rear I have in the car right now is in good shape. Or would I be better off just ditching the 87 rear, and trying, again, to find a deal on another posi rear? I was also thinking I could get moser axles for the 87 carrier, and pop them into the 91, but cost is an issue or I would have bought an SLP posi carrier.
Dyno Don
Supreme Member
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Yesterday
IS NOW:
5.7L with R/V cam • T56 with Centerforce DF clutch and Spohn xmember • SGI5 Speedo box • Speed Density TPI with custom PROM • Edelbrock intake manifold • Edelbrock RPM catback • Holley Adj. FPR • Accel 24# injectors • SLP Headers • MSD Superconductor 8.5MM wires • MSD Coil • High-flow cat • Eibach springs • KYB G2 Struts • LT1 starter • 95 Camaro Grey/Black seats • Alpine head unit and CD/MP3 changer • 145mph Speedo Cluster • Autometer A/F, Vac/Boost, and Oil temp Guages and 3 pod A-Pillar • Spohn tubular SFC's• Permacool 6-pass oil cooler w/ SS braided lines
You have all this and you are thinking about a 2:73 rear gear?
That would not be a good idea
5.7L with R/V cam • T56 with Centerforce DF clutch and Spohn xmember • SGI5 Speedo box • Speed Density TPI with custom PROM • Edelbrock intake manifold • Edelbrock RPM catback • Holley Adj. FPR • Accel 24# injectors • SLP Headers • MSD Superconductor 8.5MM wires • MSD Coil • High-flow cat • Eibach springs • KYB G2 Struts • LT1 starter • 95 Camaro Grey/Black seats • Alpine head unit and CD/MP3 changer • 145mph Speedo Cluster • Autometer A/F, Vac/Boost, and Oil temp Guages and 3 pod A-Pillar • Spohn tubular SFC's• Permacool 6-pass oil cooler w/ SS braided lines
You have all this and you are thinking about a 2:73 rear gear?
That would not be a good idea
Ah, I forgot to mention that the rebuild for the posi carrier included Richmond 3.73 gears. Right now I have 3.23 and they suck. Going to 2.73 would be insane!
TGO Supporter
if both are 10 bolts rears the carreir will bolt up. the spline count is differant between 87 and 91 so you'd need to swap them too. takes a hour to r&r the rear and several hours to set up gears, easily done in a day 
Supreme Member
I would not do it.
The older posi would require that you downgrade the axles, and you'd have to use a ring gear spacer since that's a 2-series carrier and your gears (if you bought them for the 3.23 rear) are normal 3-series.
Sell the 87 rear unmolested, and buy the $100 take-off carrier from SLP if they have any left.
The older posi would require that you downgrade the axles, and you'd have to use a ring gear spacer since that's a 2-series carrier and your gears (if you bought them for the 3.23 rear) are normal 3-series.
Sell the 87 rear unmolested, and buy the $100 take-off carrier from SLP if they have any left.