imho if that engine is similar to YB that is way to much for that rpm and pressure.
Nope, the ZVH is a hybrid engine, 2 litre zetec bottom end with the 1.6 CVH 8v head fitted.
As everyone has correctly said, there is not enough information given to answer that question. There are so many variables that could affect the engines tolerance to timing, the only way to say is to get some det cans and preferably EGT readings and see what's limiting you. May need more fuel or less timing. I take it by 170kpa you mean absolute, not relative?
I'm assuming 4000rpm would be peak torque region on that engine? .....Should be a clue there
For a review of the ignition map and to see whether it's sensible or not, we need to know the specs on the engine and a log would be preferable, but if it's knocking, I would back it down before trying too much more.
-Gavin