Hey, I have a 3310 750cfm vacuum secondary carb that runs pretty darn tight. I have the vacuum advance hooked up to the metering block rather than baseplate port. Is this correct? When the car is running it sounds like it's sucking large amounts of air and I can pinch the hose to the vacuum advance and it goes quiet and when I release it comes back. Could the diaphragm in the vacuum advance have blown and creating a huge vacuum leak or is this the way it's supposed to sound from this port?

 

Let me ask you a question. How fast will the metering block return to atmospheric pressure? How fast will the baseplate port fill back to 14.7 psi?

If say both filled back to atmosphere equally, would the vacuum advance run as stout as you say how tight running that Chevy runs? You did mean, "Tight" as tight as a drum? As fit as a fiddle. As in you have pinks, we race for pinks you are going to lose this car is that 'Tight?'

 

Tight = strong

It was the vacuum advance diaphragm that was blown.