hey guys, i'm sure someone has an answer here....
i have an '89 iroc 305tpi automatic. 2.73 rear end, i am wanting to go up to maybe a 3.42... i was wondering if i can fit the larger ring n pinion in my housing or if the whole thing needs to be swapped out? any ideas?

 

Your current gears are on a 2 series carrier. You can get deeper thick gears designed for the 2 series carrier or swap it out to a 3 series carrier allowing you to use factory deep gears.

 

It would probably be easier to find a 3.08 and numerically higher rear end to put a 3.42 in.. Or maybe find a 3.42 at the junkyard like I did.

 

Just go to a 3.23. Easy swap for any mechanic (you might not want to try this yourself unless you have a lot of know-how.)