Not hard to cut some coils but that is pretty low. Let me check the Hollander book for spindle interchange.
Yeah I didn't really want to cut them. You used to be able to get them from Jamco but it seems they went under or someone bought them out. If that's the last resort I will though
You can try Coil Spring Specialties in St. Mary's Kansas. They have a website and cater to the classic vehicle market. 60 Special
Have new coil springs made to the exact specs you want. I would recommend Coil Spring Specialties: https://www.coilsprings.com/
You could use a dropped coil, but you can also drop the lower control arm to lower the car. The 55 Olds uses a heavy C-channel control arm with the stamped spring pocket riveted in. If you cut/drill out the rivets, you can add a spacer between the spring pocket and the control arm and replace the rivets with bolts. This will give you a similar dropped effect, and will allow you to lower the car without chopping the coil substantially.
I did that very thing on a '56 I used a 1"x1" solid aluminum bar I don't remember exactly how much it lowered it but it must have been about 2" measured at the front bumper.
My family had a 55 Olds 88 like this one, but a four door. I was brought home from the hospital in that car and we had it for 27 years.