You may, like a lot of other Mopar car owners, have a fuel delivery problem
If you have the stock carb,. off of a 440 it is not to big
Trust me on that
I would go ahead and put the wideband sytem on the car and use it, it will tell you right away about the fuel supply system, if it starts to go lean at the higher RPM, especially in high gear , it is runing out of fuel
Been there done that with all good parts
There are a lot of gremlins that can affect fuek delivery, a lot of them
Let us know waht you find out