then you just need to understand the fundementals behind boost control and bleed valve, so best just to get it done by a pro imho (mistakes can be fatal to the engine)
And its properly random how an AMAL valve works
its all back to front.. just get someone to re-jet it properly for you!
AMAL valve is apparently a ford only item so you will have to get one from there if you need a new one
CheeRS
Phil
P.s they arent cheap