Mechanical v/s Vacuum Secondary Carb

I recently did a similar posting and here is the link to it.  I had been using MS carbs and now have a VS carb and I am really enjoy it.  There are a lot of helpful comments in the discussions.  FYI, I never smelled gas from my MS carbs including the 750 double pumper.  I am still using it on another Pantera and it works well.

https://pantera.infopop.cc/top...s-vacuum-secondaries

Also, one of the noticeable differences between MS and VS is the feel of the gas pedal.  There is resistance from the MS half way through as the secondaries and accelerator pump engage.  On the VS the pedal is linear all the way through even though the secondaries are fully engaged.

My friend says he likes MS at the race track and VS on the street.  He said the MS produces predictable performance (hundredths of a second are important) while the VS feel of the gas pedal is friendlier on the street.

Steve, Thanks for your input. Lots of info here.

Before you change carb are you sure the gas vapor is coming from the carb? Maybe from the tank vent, fuel lines or a weeping  tank?

Fuel tank and fuel lines seem fine. Not sure if vent hose is connected to a charcoal canister or even if there is a canister anymore and the hose just being vented to the atmosphere.