I run the Nitto's on my 69 fastback and run them at 16/17 psi depending on track prep.I had to put screws in mine also as they were spinning on the rim(my 60ft improved also)
The more I think about it the more I think the tires were spinning on the rims, more than just 180 degrees. I am going to have them dismounted and clean the lubricant off the beads and put the screws back in. I am ever glad I didn't decide to weld all the screw holes up!
