Too much cam?

Quote/ 67 Dart, 360 with roughly 9:1 compression, magnum heads, air gap intake, 670 Street Avenger carb, 3.23 gears, 727 and stock converter in a 67 Dart.

Last year I swapped out the Edelbrock cam (smaller of the 2 they offer) and put in a Comp Cams 270H (specs .470 lift, .501 with the 1.6 magnum rockers, 224 degrees duration @.050, rpm range 1800 to 5800). The cam was installed 2 degrees advanced. I have an FBO ignition and it calls for 16 degrees initial timing. It idles at 650 rpm's with 15 lbs of vacuum. I did the power valve, secondary spring and different jet experimentation with no real change. /Quote

In my opinion that cam is to much for the converter/gears/carb and compression that you're running and the 1.6 ratio rockers ain't helping. You might want to try a set of 1.5's and yes verify the cam timing for sure.

Terry