Help me pick a new carb

Carburetors are much the same as camshafts when it comes to choosing. You will be MUCH happier with one that's a tad too small than one that's a tad too large. Vacuum secondary carburetors have more forgiveness in that area. I think with your combo you have described, if it was me, I would use the Holley Street Avenger 670 and not even think about it anymore.