Whiplash cams

Dave at Hughes also was trying to sell me one of these cans. He said because my engine has low compression but I tried to explain to him that the compression was 9.7 to 1 on a magnum engine. Something tells me that there might be a better cam without so much lope maybe a 110 instead of 107 I don't need that much lope I need performance and fuel economy not so much the sound. Any help would be greatly appreciated before I drop $400 on a cam...