There’s a ton of info and discussion on that topic for sure, but the general consensus that I’ve seen is that a single makes more power. Using headers typically gets a single pattern recommendation from any cam company no matter what heads are used. I found that to be the case when inquiring on cam selections with Isky, Bullet, Howard’s, Jones, Schneider etc regardless whether it was a 360 mild build or a 410. The heads (stock smog 360, Speedmaster, EQ or Trick Flows) made no difference. Again, if I mentioned headers it was a single pattern. Only time I got dual pattern recommendations (Crower, Howard’s, Comp) was from (IMO) seemingly newbie novice “email responders” and they were dinky spec’d cams at that.