1973 340 detuned?

Running a stock distributor.

Unless you have emission testing to deal with, one way to make it run better is tune your engine with the initial timing it actually wants. The book numbers suck for performance and idle.

If a stock 73 340 doesn't ahve at least 14* on it, it's likely not in the range it should be. Timing it this way takes work because you have to fix the distributor mechanical advance as well.