Best bolt on?
Converters need drag radials to really be used though. 
I tried to stall it at 1500 RPM and then floored it, that was a HUGE mistake. Just spun in one spot burning the tires, then fished one way, corrected, then fished the other way facing the wall. Let off the gas, straightened her out and then rolled into it. Got a 15.2 @ 101 with that.
Best bolt-on for a M6 is a lvl 4 4L60E
And then a torque converter

:lmao:even i gotta admit that was funny...






But I don't care if I'm slower as long as I'm having fun