Couple of thoughts/questions

1) Something is off with your combo - you are not trapping much more than what a basically stock 383 should trap in a stock weight B body, with stock converter, 4.10 or less gear, etc. That would be a good running stock 383, but nonetheless its been done. With headers and good exhaust a stock cam would make the same MPH. You have more cam, a better intake system, and what must be a healthy short block with 175+ PSI. Sounds like this is not a low comp 383 either.

2) You may have too much converter - didn’t look like you came up on the converter much on the line but it looks like you’re only dropping to about 4500 on the shifts, I would think it should be coming down a bit more than that from only a 5500 RPM shift point (it looked like you pulled second at more like 5200). Are you sure the converter isn’t looser than 3500?

3) I wouldn’t condemn the cam yet, but if you want to go back to what you had if you had the 509 Mopar cam the Racer Brown SS-H-44 is supposed to be very close

4) Did you degree the cam? Did you make any change to the fuel system? Did you change the pushrods, or check your lifter pre-load? Your pushrods may be too short and causing additional issues.