I need a little enlightenment on this Holley carb
You know that isn't a 2 barrel Holley, right?
It's a single barrel Holley 1920, imo number 3 on the top 3 slant carbs. If it works fine and you like it, awesome. But they can be problematic, esp. when it's a reman like that one(the sticker on the bowl).
I personally would rebuild the Carter and use that since it's a better carb with the correct ports. Plus I think the choke might be different between the Carter and Holley but not sure.
If the seller represented that as a 2 barrel, send him a 2 line message:
On the first line ask why he did that and on the second line demand your money back. Good luck.