As the title says I am trying to tune the carb and need to find a vacuum port on the intake of the 58 292.  The only thing I see is a square head bolt in the intake almost directly under the carb bowl.  Is this it?  Is there a secret to taking this square bolt out?  Is there a easier location for another port?

thanks again

Cbass

1958 F100 292

"Nothing is particularly hard if you divide it into small jobs."

"Chop your own wood, and it will warm you twice."

-Henry Ford