Right thanks, any idea on kind of boost level that would amount too?

It has full boost by approx 4k rpm, but it spools from 1500-2k rpm.

If i put it in fourth at 1500rpm, and let off at 2k it will dump and you feel the
extra 'turbo power' as such at that 2k rpm.

Also, i know this has been covered before many times, but im really not sure on what running in miles to do?

I have new rod mains + piston rings, the crank mains etc are all original and have not been unbolted.