In 1989. I raced at the asphalt 3/8 at Lebanon Mo.
Flathead were hitting 70 mph in the draft.
We started 54 karts in a grand prix start.
I missed gear horribly, but led the field into turn 1.
I believe the track had progressive banking, 7 to 30 degree in the corners.
My advice is to be sure your tires are balanced. My lungs hurt for 2 weeks from the vibration in the corners.
The 2 smokers were hitting over 90 mph.
It was awesome fun.