Idles better is becuase you plugged the vacuum leak / corrected fuel air mixture.
You can replace only the vacuum servo if you can find one. Some of them aren't readily available.
Some guys do adjust the base timing to prevent pinging under load when running without the vacuum advance. One thing leads to another though. 14 to 18 degrees BTDC can stop the ping but cause harder to start. Then lower the curb idle to prevent run-on or diesel at shut down. Shade tree tuning at best.
A reman'd distributor will include a new advance servo.
