Hi guys, first post here. I have read that 98-11 crown vics have spring perches that support 2.5” outer diameter springs. I also have read that rear springs for 79-11 vics are also interchangeable. My question is, could a 2.5” ID coilover spring work on a box (in my case, a 1988 town car)?
Would using a slightly wider 2 and 5/8” ID coilover spring work? Or would that be too wide for the perches?

The reason why I want to use coilover springs is because I’m wanting to get my car super low; my plan is to use afco 1020 and 1031 shocks paired with lowering springs up front, and hopefully coilover springs in the rear so I can cut them to really get the exact ride height I want.