First launch in new big block cuda - video

I would try leaving off the foot and not have the suspension all tensed up by leaving off a two step.
You have a dinky convertor to begin with, off the foot at lower rpm might hit it harder, plant it better.
The 60 foot you are getting from it is because you have 500 inches of torque producing motor on tap.
Your currently getting the performance of a stock stroke 360 with Eddie heads.
I have no idea where to start, at that weight, car should run 10.20’s with what you have