Which type of carburetor?

I just bought a used Eddy Performer manifold for my 360. The carb mounting flange is for a spread bore carb. My question is should I put a spread bore carb on it or a square bore carb with an adapter? Also, do I need, or should I, enlarge the runners to 360 size? I'm assuming that since it fits all LA engines that the runners are 318 sized.

Thanks.