Seeking advice intake manifold

The Edelbrock performer is a spread bore just like the cast iron manifold, difference is the weight as the cast iron one is heavy. Because you have a 340 you can port match the Edelbrock to the 340 heads.
BUT a daily driver it's not necessary.The Performer ports are smaller than the cast iron intake. Not a problem in my book.
Used you can find 'um cheap while you are at Carlisle.