As you are finding out, all Holley 2300 carbs are not the same. There are original design models as well as aftermarket models, with numerous variations of each design. The original models have a side hung fuel float, while the aftermarket models use a center hung float. The corresponding fuel bowls are markedly different in design and appearance between the two. Mixing and matching of random carb parts is rarely an advisable practice. Doing so can lead to performance issues and considerable frustration. If you could provide us with the list number of your carb as well as the list number of the parts donor carb, that would help us help you determine whether or not parts between the two are compatible. The list number can be found on the front, right face of the airhorn and will be a 4 digit number possibly with a suffix such as 2977-1 or 7448. If you'd like to post good pics of the carbs that could be helpful as well.