I have a 3mm street ported engine and the boost is 10 psi right now. My mechanic said that it is equal to the 14 psi boost of normal engine? Is that ture?

 

He is basicaly talking about the boost required to produce the same amount of power between stock and street ported engines. You also need to take into account the differences with the exhaust system and IC between the too. 10 to 14 might be close comparing a completely stock engine to a prepared ported engine.