Upgrading my 340

Killer;

Then if you are correct, then explain forced induction relative to vacuum.

You can't and therefore your wrong.

Carbs do not work on vacuum alone.

A forced induction is pressuring the engine. Above and below the carb. It is the air flow going past the carb gas ports in this manor. Not vacuum.
I can, and You're wrong. You are stuck on accepting vacuum as only something below ambient atmosphere. Do You know why velocity even exists? It is
due to flow, and flow only occurs when a pressure delta is present, no diff. in pressure...no flow. As I already explained, charging is increasing the local atmosphere
above the carb(on a blow-thru), so 15psi above,& 14psi below = roughly 2"Hg of vacuum at the boosters.