Is the standard engine safe to 8000 rpm?
No!
What have you done to the bottom end to support the extra power and revs you are getting now?
Nothing! However, I've implemented a rev limiter in the EMU Black software

Sorry if I missed this in your earlier posts.
You've missed noting IvorMog, but just because I've proved the engine can go to 8,000 rpm and will keep producing power all the way until it gets there, doesnt mean its sensible to alow it to do so

I'm pulling out at 7,500 chaps, well, actually I start pulling timing from 7,300 on before the hard fuel cut chimes it at 7,500 rpm

The point is the data proves what an amazing engine the Duratec truly is and how well the FF inlet and exhaust are supporting it so it can deliver its full potential, no wonder Caterham have been using it for years... and still continue to do so!