You just bought yourself a financial can of worms. Rewarding if you can go the distance. Both 40s and 45s will work (45s may need to be choked down for the street). Carbs will set you back $400 +/- and you may still need to have them rebuilt $$$. Try to get the carb linkage with the carbs if possible as it is pricey. To maximize the set up, you will need a better than stock cam and a header. In my opinion, the rear end gears should be minimum of 3.73 but 4.11s are better to take advantage of the higher RPM. 7500RPM with 160HP is easy with this setup and it will definitely have the WOW value under the hood.
71HANTO