Seems to me you already identified the problem being the carb in Post #3, and both Hoss and Firebird pointed you back to it in #4 and #5. It didn't pop with the Holley, you're in good tune across the rpm range which says the jets are right in the Edelbrock, but it pops in the transition. Fix your accelerator pump. You're going lean with the inrush of air at WOT, and you're getting a lean pop on one or two cylinders as the intake is closing.