Where's the boost??

[Zac]

I was going to suggest loading it up a steep hill on light throttle but then noticed you're in the Netherlands

[oldcorollas]

I'm running blow through Holley 650 double pumper

The top is cut out in the middle because I have an Impco mixer in the filter box..

so are you running gas or petrol?

[BigMuz]

Take the dump pipe off and try it again- maybe you are restricting the exhaust flow WAY too much.

Do you have some more pics of it finished?