Turn the bowl upside down adjust float to just start to rise with a 3/8 bolt slid between the float and the lower side od the bowl. Thast will get you very close to proper float level. There is a u-tube video from Holley on how to do this.
Good Luck

If you are sucking on the vent line going to the fuel pump you are putting neg pressure on the other side of the diaphragm inside the fuel pump and just not allowing it to operate at full capacity.....Picture a sub-woofer in a stereo system....when its in a box and it has a vent hole it can move in/out freely. If you plug that vent hole the sub will still move but if it moves less cause its working against that vacuum in the box now when it tries moving outwards.

Thank you ill try that...ill have to recalculate

Is that the way it should work..

That vent line coming from the fuel pump should go to the spark arrestor (air filter)...there should be little to no vacuum on that line. The only purpose of it is to flood the engine in case the diaphragm breaks inside that fuel pump. 9psi shouldn't be the issue.....ive used a small electric fuel pump on a carb before that put out 10psi and still worked just fine. Its the carb that the problem....most likely the float needs to be adjusted more.....unless the needle is sticking for some reason...

Zole, when you rebuilt carb, whose kit ? Sometimes the holley needle and seats seem to hold more pressure.

Also, fyi, parts aren’t as good as they used to be. If you search the net you’ll see several people with high psi problems with random aftmkt and oem mech pumps. If too much psi really is your issue, msybe an inline adjustable regulator may he your best bet. Especially since you being overseas. (Expense and amt time for shipping including returns)