5.9 Magnum flywheel - DIY with bolt-on weight??

yeah timing is set 15 initial, 34 degrees total, plugs gapped for .35". I even had each plug wire off checking for diffrence in sound (you could notice when each wire was unplugged).
played with the carb non stop, kindof figuring its not my carb because it was running on my 318 2 days before first startup on the 360.
right now it is smooth as can be anywhere over 1400rpms but then you start to notice it the closer you get to idle. at idle it sounds like it has blower surge or something fluctuates 200 rpms. could it being that little out of balance cause it to idle wierd like that?