Not sure if this is my real or only  issue but here goes. I am running the same clutch /gear set up as before. The only change made was a new brain box that holds the timing in a more advanced state till further up the rpm range.   It still ends up in the last 500 rpms almost matching the origional brain box curve. Its crisper in the first 100 feet or so but my driver feels it is taking longer to really settle down and pull hard on the big end.  Do you think this could be a carry over or delay caused by this ignition ? Or am I more likely chasing a clutch overshift issue now ?  MMR

I have graphed the origional brain box & have the info on the reburned brain box. I have verified the new box is doing about what it is supposed to with a timing light. this is a 9400 rpm drag race motor.  The new box steps & holds a lot more timing to 8000 & some more till 8500. Then it sweeps down to 9200 & is actually slightly less advanced at that point than the origional. I found out the hard way it needs more pilot down around the launch rpm . Knowing how fast these motors get to peak rpm I was just wondering if someone with real experience with these newer reburned brain boxes could shed some light on this. What did they experience with a simular change.  (This delay in downtrack charge ? )   Am I chasing a timing issue or is it more likely a need for additional jetting changes or clutching.  My prior jetting & clutching set ups with a stock brain box were excellent . MMR

Thank you. I hadn't considered pipe temp being the issue.