Actually, a vacuum advance runs reverse. Low vacuum = more advance. An engine creates less vacuum at WOT than at idle, so a low vacum big cam could cause the vacuum advance to start kicking in at low RPM, causing a stumble or miss at part throttle. Unless it's a light car, with a big gear and a 3500 or so stall, that cam is not streetable. If you're not going to run it over 6,000 RPM all the time, put a smaller cam that will match the way you're going to drive it. Those big SEXY cam specs sound good on paper, but your engine will be a low end PIG. As Carroll Shelby once said, Horsepower rules the track, but Torque rules the street.