I am running since I put in my msd 6AL a acdelco 41-993(19256067) iridium plug. I had acdelco rapidfires before that #14's. I had no knock issue when I was running the 7747 computer with these plugs. When I swapped to these the motor ran smoother. I know to stay with acdelco or ngk since they make the acdelco plugs. I would not be opposed to trying these just need to get to the parts store and get them.
I will have the new knock sensor (ks6 standard) tomorrow so hopefully get it installed tomorrow night.
I tried a starter timing table that Fast355 posted on TGO for vortecs, he said that he uses it as his starting point for stock to mild cam motors. I tried it and seemed to work well except high rpm high map, upped the timing there and just from one adj seems to run pretty good, still needs refined. Here is what fast355 posted and I modified it for my spark table. maybe this will help others as it was pretty good for the first drive.
Attachment 14290
Fast355 if you are around maybe you can chime in on this and if you have made any changes over the years on this for your starting point for the vortec heads. I would think 30* is high at idle but I did not get knock.