I found that plug gap was very sensitive in the alky injected Rons toilet setup, just some food for thought.
I made more than one change at a time, cause I knew they would both be in the right direction. One was a new set of plugs that I gaped kinda wide like .048-.050. The car slowed down from a 4.90 in the heat to 4.93-4.94 It took me awhile to figure it out too.
My ignition system was probably border line to began with, being a large engine with lots of compression 15:1+ the 6AL must not have had the oomph for that many rpms. 7400+
Anyways, gaped the plugs back down to mid .030 and the e/t responded