Engine misfire or loading up when opening the 4 barrel.

Remember new doesn’t mean good. Check new parts as they go on the car. Especially fuel delivery parts. A bad fuel pump commonly causes the issues you’re having.
How would you check the fuel pump? It came from O’Reilly. I did change the dual line feed to one of the ones that has like a JIC type fitting that comes out of the carburetor to a braided line with jic fittings as well. It has a gauge in line but it doesn’t read. I figured there’s just not enough pressure to show I mean, they only usually push about 7 pounds