The cam I have isn't too big, it is around 240 @ 050 hyd roller and it idles with about 12 inches of vacuum. I manually adjusted the AFR at idle from 12.5 to 14.5 and the engine didn't seem to care. I adjusted the fuel map to set the idle at 13.5 and then turned closed loop and learn off below 1200 rpm. So I think that will work but I'm sure I'll need to keep an eye on it.