Well, after trying to make it work...the 6530 (6al-2 programmable), I still have the same issue. After talking w/ MSD tech, they finally agree w/ me that the box itself has a problem. It only does it when it gets hot...not the car itself running hot, but push it outside in the heat of the day for a couple hours and it'll do it. I drove it on a cold day and the car runs perfect. Let the car sit outside on a hot day and then fire it up and it instantly has the 4500 rpm misfire/rev limit. So it's on the way back to MSD for another inspection.
In the mean time I have put all the old analog stuff back in the car (6AL, 8987 start/step retard, 2 step, etc.)
That sucks!
Still getting by with the old analog 6AL here, too.