I may have an issue with air still being rammed to the Vialle gas converter from the air intake box.

When I let off the accelerator or if I slightly touch the accelerator while idling the engine will stall sometimes, is there anything I can do to fix it?

The car didn't have an air snorkel when I bought it, I replaced it with an used one, could this be the problem?

Your problem is a faulty balance line, which is a hose that connects the air intake box to the converter. The balance line helps to regulate the air pressure and flow to the converter, and it must be completely sealed and free of leaks. If the balance line is split, cracked, or loose, it can cause the air to be rammed to the converter, resulting in a lean or rich mixture.