Member Greg55_99 has experience installing different K Frames into an FMJ.
As being that you're eliminating the torsion bars and going coil overs, the K Frame will see a lot less twisting load.
Are you going to be caging the car?
How are you going to support the tops of the coil overs ?
I'm thinking of using an SW complete strut front end kit, replacing the factory front Frame rails. Car will see some street use and will be in the hi 8's low 9's on the track.