Best 60' so far was 1.98 but I still haven't got a clean launch in
I have a circle-D multidisk 3600 converter and it helps to lock converter for sure just got to play with it to find sweet spot to lock! Had to move mine a time or two

 

so on the 6 speeds with converter and 411s is good to lock at 70 mph at full throttle is what ur saying?

 

im running the yank 3600

 

Mine shifts into 3rd at 60mph so I lock mine at 70mph but am prolly gunna move it to 75mph! I also lock it in 4th too at 105mph

 

Just try and find where it likes to lock in the power and the best! My truck is very heavy so it may be diff for you also cam specs differ