You've got plenty of vacuum line left over.
Now remember that I don't have any vacuum advance on my engine when I write: "If the joint uses a compression fitting, just get a tubing cutter, cut the messed-up end off and use an appropriately-sized compression ferrule to make a good seal. If it's a flared tube, just slide the nut onto the tube and flare the fresh end and throw it back together."
Incidentally, if there was a vacuum leak where the tube was broken, not only will your ignition timing be off an higher RPMs, but the mixture could be off and the engine could run poorly even at lower RPMs, depending on where and how the vacuum is sourced on the carb.