I am about to swap my 1989 Iroc 2.77 BW 9 bolt with a buddies 1988 Formula 3.27 BW 9 Bolt rear. Both posi still lock but i am making sure i keep my breaks and rotors. Our mechanic wants to completely rebuild the rears before the entire rear ends are swapped. Is there anthing else i should look into???? I have been hearing 2.77 to 3.27 is a nice jump for street driving. Besisdes the elusive BW 3.45

thanks for all your help


JOHN

 

you should have a clean swap as long as they both have the same style brakes. just drop the two control arms, the panhard bar, the torque arm, disconnect the brake line, and the driveshaft. put it in the reverse order of how you took it out and bleed the brakes, and you are done. it should take you less than a day to complete, and you will notice an increase on your acceleration. you should probably change your diff fluid while you are swapping it out, no harm in it.

 

I swapped a 3.27 into mine from an '87 car, an older rear with the old delco moraine calipers. I replaced my 2.77 with it and it was a nice jump, really liked it. The only thing I did notice is I used to backing plate from my 2.77 pbr brakes on the 87 rear, and ended up having to shim the caliper mounting brackets out just a hair to make them clear the rotors. No biggie, it's the only issue I had. You will also want to swap out your drive and driven speedo gears to get the correct mph. I have yet to do this on mine, but I will soon. Expect to see something like 85mph when you are crusing at 65mph. It's worth swapping out the speedo gears