Of all the H-series Comp cams, the 260 seems to offer the best compromise between power and smooth operation, at least with the 20-some ones I've personally dyno tested. Around 268 degrees of duration where the "Magnum" cam series begins is where a noticeable idle lope starts happening, and power brake and other vacuum-related problems begin. A programmable computer chip that allows for some tinkering with fuel mixture and ignition timing advance is also helpful.
Jerry
