Hi,

I remember back when I installed 150 bar pop pressure injectors on my 617a SD the dynamically measured delay was about 2.5 -3 deg compared to the old ones with almost 140 bar.

Worse starting and hard nailing even when warm will tell you that it is too much advanced.
Please report your experience as the 603a engines are more sensitive and I am also playing with timing and pop pressure.

Tom