You did something wrong in a big way but the first issue is the engine was a bracket engine and not a good combo that way it was set up in the second problem you had….
Heavy heavy car! WOW! Way heavy! 3480?!?!
Holy cow!
What was that stall converter flashing at?
That “$” sign as the first digit is a mystery.
What “Low gears” were added? Ratio?
How about tire size?
I met a bunch of dudes running that 360/380 create engine, as delivered, no changes, OOTB into the car and ran it into the high 11’s. (Not that it was an easy thing to get done.)