I have an '89 Camaro that has 3:42 open rear axle in it and a "87 S-10 Blazer that has a 3:73 locking diff under it. What I'd like to know is this, can I swap the carrier and gears from the Blazer into the Camaros housing?

Any help would be great.

 

Probably; although your 89 may be one of the few that got the later-model axles with 28 splines. The 87 stuff will have the 26 spline stuff.

The gear is OK; but you don't want the carrier. It's the notorious Eaton "Grenade-Lock". It's not exactly a "posi" at all; rather, it acts like an open, until the RPM difference between the axles exceeds some threshold value (100 RPM or something), at which point it locks up with a bang. If it has both power and traction, it tends to explode, literally, when that happens; which is how it got the nickname. One member here put one of those in his car, and then posted a lovely pic of the hole in the gas tank made by the shrapnel from the explosion. Several people have posted pics of their rear end covers with holes in them. It's bad enough with just those weenie 6-cyl motors they put in those trucks; just visit the S truck boards and see what people there think about them.