[tjyak50]

Feedback.
I put the carbs in a CNC mill and had the boys drill the 4th hole (closer to engine and directly over the butterfly). .030" hole about .030" downstream of the old hole.

Car ran extremely rich.

Then I plugged the old "1st" hole and it runs like a dream now.
No leaning out on part throttle, no spitting or sneezing.

Its about 115f here in Phoenix today and my extra layer of thermal blanket even kept the carbs from boiling. (Z motor carbs sit ON the exhaust - stupid).

So far my experience with adding the 4th hole is good.
FYI>
TJ