An RV cam is just the description used by many cam manufacturers to describe a cam that gives more performance in the low and mid range rpm band. You would have to look at the advertisements by each manufacturer in the magazines, because all of them have a slightly different idea about what the term RV cam is supposed to mean. You can think of an RV cam as a mild performance grind. Think more low end performance with limited top end performance. You can't get something for nothing, and the cam profile is one of the determining factors on how well or how poorly an engine is going to run in a specific application.
Bob

55 Cameo 396 TH 400 with overdrive
65 Caliente conv
67 BB Caliente conv
67 Mercury 1 Ton
76 GMC 3/4 ton 454ci
84 Buick Turbo Regal