try pulling the wastegate line off
but back off if the boost goes crazy
if that works look at replaceing ur bleed valve
and haltec can have a boost cut programed into it
to do that head swap involves a lot of work
it can be done but it would cost a fourtune
i have seen a rb20 head on a rb30
and it needed water jackets and oil galleries all need to be moved
and i think the valves r bigger on the rb25
i was wondering if anyone knows
the dyco part number for the rb20det timming belt
i tried to buy one today and the spares place
didnt know the number
thanx heaps
u can by an adaptor from any spare parts place
u will probarly find where u bought if from has it
i know autobarn have them in redline brand
hope this helps