When I first prepared the tuned 604 Nordwest for speed hill climbns and limited road use (the annual IoM trip) I put Pirelli Dragon Corsas on it. Pretty good and inspired confidence through Guthries on a closed road.
When they wore out I replace them with standard Dragon Evos. Still OK.
Based on how well they work on the GFRs (at Cadwell in particular) I would probably just put 'H' rated Diablos on now if available in the right sizes. Who needs a 'Z' rated tyre on a Nordwest?
"Do not adjust your mind, there is a fault in the reality"
1957 175 Sport