911 sc ride height

[kmhemi]

I need to raise the ride height on the back of my 78 911sc. To adjust the spring plate cam bolt does it require a special flat wrench to hold the bolt on the inside or is the plate threaded?

[Schrup]

You need a 36mm X 24mm thin wrench like the one in the pic. I picked on up at a bicycle shop for $12. The host sells them.