i have an 80 cutlass that the previous owner put an A body rear end in with a new eaton posi and 3.23 gears. he used the south side machine control arms to make this work. I want to pull this rear end out and put it in my 69 cutlass. all measurements are the same only difference is spring purches are on the oppisite side of axle. will this make a difference? looks like spring angle wont change alot.

 

You really should put that spring perch hanging off the front of the axle tube as it should be. It helps keep the pinion angle correct and under the upper spring pocket of the A-body car.