Yes for starters lower it, loosen the lock with the flat tip and turn the nut about a half turn in a clockwise rotation, reset the lock and try it with it there. You may have to floor it still to get it started at first, but this will give you some idea on where it`s at, if it`s still too high, repeat the step above. Be advised also, if you lower it too low, the nut won`t adjust it anymore, then you`ll have to remove the lock and the nut and turn it back out counter clockwise. If it gets like this and it`s still flooding, then there`s trash in the needle and seat or there`s too much fuel pressure.
After you get it baselined, you can set the carb from there.
If you used a open adapter to bolt the holley on it likely won`t tune out like it should, and if you never changed the distributor to the older HEI with vacuum advance and mechanical advance now would be the time to do so.