I'm assuming your running a Rochester M2ME
Those carbs are a heartache, yes they do have adjustments, once you
drill away the casting flash that hides them.
Best bet is to spring for a new carb to manifold gasket and do
the drilling with the carb off the engine. Slot the adjustment needles
too, or epoxy a nut to the end, and use a nutdriver to adjust carb.
Some needles are already hex shaped, some have a goofy end that you can
twiddle with a piece of flattened tubing once you can get at it.
You may consider a rebuilt carb, as those things are a nightmare
to rebuild. The rebuilt should come with " improved " mix adjuster screws.
A trick setup would be a 4 Bl to 2 bl adapter, the 4BL side should
bolt to the manifold, the remaining hole capped with an old
Rochester 2G carb. AKA the 2 Bl toilet, as it's so simple and
straightforward to service [ like a toilet tank ]