[DaveR_GT]

While a different cam may help. The car should still run with what's in it.

Search around I know you can find lots of threads here and on other mustang boards about surging. And you should be able to pull codes from the computer to help also.

I would worry that if you don't try to fix the symptoms now, they could still be there with a different cam.

What else was changed? Throttle body? MAS? Injectors? If someone put heads and cam in they likely changed some of these things also, or if not maybe they need changed to keep up with the thirsty engine?

Just some food for thought
Good Luck