Those cams are really for those that don`t know how to make a basic high performance cam lope at idle so really it`s nothing more than a sales pitch cam that costs power. My friends cutlass has a Vortec 350 and we installed a Comp .218 duration @.050 cam. It says "Noticeable idle" and it does, it idles with a really nice lope and it doesn`t cause any power loss.
I played with timing figures for a long time when I learned how to make them lope. That same friend of mine purchased a chevy truck not long ago with a build 350. The thing ran decent,, if that`s the word for it. Anyways, it`s got a set of headers, 882 junk heads, a edelbrock intake and carb. When he got it, it idled smooth, he was told it had a lopey cam in it, but it didn`t sound like it. The thing was completely gutless on power. So he brought it to me and left it a few days. I did some work on it and when I took it back to him it had a nice lopey idle. The guy he bought it from came by and heard it run and wanted to buy it back on the spot. He asked me "How did you make it lope?" and all I said was "Nothing to it"