Nitrous on a 340 100 shot

The pcv valve is basically a large controlled vacuum leak. If the carb was tuned originally with the pcv and it is removed the tune up should also be changed. They can and will make a difference in the idle tune up. Your next step should be pinning every single hole in the carb. Do not make any changes until you know what size every orifice is and have them written down. That’s step 1