I had no idea that a roller cam can make that much difference, making a huge cam look much smaller to the engine. If I'm all screwed up in my thinking someone please correct me, but it sounds good on paper.
lol
Works good in real life too.
A roller with same numbers will give you a whole lot more rate per degree of rotation and under the curve than you can possibly get with a flat or hyd flat lifter. The actual engine will behave like it has maybe 10 degree less duration at .050 as far as idle traits go. You can also give it a little wider lobe separation and the idle gets smoother and the idle vacuum increases too.
Ed