Watched an Engine Masters episode the other day on using same lobe cams but different LSA to see what difference was. Tighter LSA made more HP up top but the wider LSA cam had a broader HP/TQ curve (flatter) than the tighter LSA but did make less HP up top
Comments were for a "street car" where it isn't about WOT only use the wider LSA even though it made less peak HP would "feel" better on the street as the TQ and HP was in at a lower to mid RPM range that is the majority use of street car driving
Of course they're going to get that result if they use the same lobes for each cam. When you widen the LSA and keep duration the same, you decrease overlap. And it's overlap that determines idle quality and where peak torque is going to occur, NOT duration. The design of that test is flawed.
You can't really blame the magazine guys, though. 99% of hotrodders are fixated on duration, so of course their test had to focus on duration to connect with their audience. That's why the cam companies have to widen the LSA in the first place - to keep their customers happy; not produce the best engine numbers.
Just out of curiosity, what were the specifications of the cams they tested? I'd like to compare them to the numbers they got in that Popular Hotrodding article I linked above; particularly since it was the same group of guys (Steve Dulcich, et al) who did both the EM test and the PH test, and on the exact same dyno. The heads will make a difference as well, but we can still get somewhat of a comparison by looking at the dyno curves.
One thing the EM test does prove, since the duration was the same for all cams, is that it's overlap, NOT duration, that determines the power curve and idle quality.
Since everyone but the hard core guys pick their cams based on idle quality and every day driveability and NOT peak hp numbers, it would make a lot more sense to test cams that have the same idle qualities but different LSA's and lift durations. We can use the OP's cam to start with and go from there.
206/206 dur @ 108 LSA = 42 deg overlap (at .006")
206/212 dur @ 108 LSA = 45 deg overlap
212/218 dur @ 112 LSA = 43 deg overlap (OP's pick)
218/224 dur @ 116 LSA = 43 deg overlap
Using Comp's Xtreme Energy cam lobes #3311 (206), #3312 (212), #3313 (218) and #3314 (224), all of those cams would have pretty much identical idles because their overlap numbers are all nearly the same. So the only reason to choose one over the other would be their performance on the dyno. If you were able to notice any difference at all in idle quality, the 206/212 cam would have the cammiest idle of the four, although the difference is so small I doubt most people could tell which cam was which.
For comparison, the stock overlap in the LT1 vette is 41 degrees and the LT4 is 46 degrees.
So all of these cams will idle about like a stock C4 corvette.