I doubt that it separates 8”. Separation is dictated by instant center location. You run Cal tracks, so the I/C is short and high. It’s going to separate. You can slow separation with tighter rear shock rebound. As long as it doesn’t spin that will help. But it will not decrease 60 ft a great amount. You are still in the area where you need power/converter flash/tune to come in earlier. How are you checking the converter flash? Converter can make or break a combo. I would have never bet my 15-1 572 would need over 5700. 6000 flash was worth a solid .10 in ET. Why low power NHRA stockers 60 ft so well? Loose converter, optimized carb, and high starting line ratio.
Doug