Boy, does my son's slant run crappy!

Jerry
If I read right you purchased a reman carb. This type of thing has happen more than once to me. These carbs just die. I went thru 6 of them once and finally gave up and went to a new 4 bbl. BTW SS Dan has NOS ones that I have bought and they have been great.( it was cheaper than a reman).

Did you ever change the fuel lines in the front and back at the tank?

It is possible that you leaked the fuel back or boiled it off over night. Check the temp of the carb after you stop. Or leave the hood up over night and check it then. Are you having to crank a lot to start the next morning?
Frank