66 dart with 360 ...what manifolds or headers?

I had 340's on my first 65 340 back in high school. manual steering and I think there was a very close spot on the driver side. I have magnums on my motor now but its not in the car yet. Saw a pic of a magnum logged 65 at a car show but no details on steering shaft where some one said there was an issue. looking at those tests makes me wonder why the fuss when choosing logs, they are all within about 2% of each other. BTW the early magnums had 1 1/8 outlets which would maybe nudge them ahead of the 340's in total flow potential, and both sides are identical. are they showing 2 varying tests per magnum side? kinda hard to determine from the posted link.