Setting timing on 1954 Blue flame 6

Hi There,
Am still having problems with engine surging at high RPMs. I checked the timing again with the timing light, and found it a bit off. I timed it to a white mark on the fly wheel, but have heard from other sources that a better way to time the engine is with a vacuum gauge, as modern fuels have changed, what was once considered the proper timing setting back in the day. Any thoughts? To recap the engine surges at high RPM in 1st gear, and when the transmission shifts to 2nd, and the RPM drops, the engine runs fine and settles into a nice rhythm. Maybe I should be looking at the carb.
Thanks for any input.