Hi I've had some surging issues as well.
170 cid 3 on the tree 64 falcon station all stock with pertronix and coil, pony carb.
What helped me was I used a vac gauge to tune the ignition. I've got around 21 inches Hg of vac. My advance is about 11 or 12 deg, no pinging.
I also changed the plug wires and the cap and rotor (basically a tuneup).
What helped most was a replacement of the muffler with the piece of pipe running from just bafter the bend over the rear axle. I culdn't get the original stuff, so I got a bit bigger pipe and a "sports"muffler with DB killer (for less noise) The better flowing muffeler did the trick I think. I've got better acceleration, better milage and no surging anymore.
Good luck with the hunt.
Rinke