Harold:

(Copy of email to Harold)

Sorry I'm so long getting back to you.

The "Block" carb wasn't machined with any great consistency, so there's no
set number of turns open for the low speed screw.

But if you look in the intake, with the throttle fully open, the gap between
the idle needle and the end of the spray bar will be close to 1/16" when
it's set right, sometimes a little more, but this should get you running.

Bill.