To small fuel line size can restrict the fuel flow, bigger size won't make the pump make more pressure so no, it won't make the carb. run worst
Which Holley list number is your carb? The list number(Holley part number) is on the front of the choke tower on the drivers side
Did you buy it new or used? If used post the list number so we can look up the stock jetting so you can verify if it has the stock jets or not
Many things can cause a aftermarket carb to run rich on one motor and not run rich on another, similar C.I. motor of a different brand