From the article building Building Mopar Engines for Performance: "The original high-performance 340 intake manifold was the dual-plane Edelbrock LD340; it looks like this newer version for the A-engine. The LD-340 was designed for the standard Holley/AFB flange and updated to the spread-bore (shown) in the 1980s" View attachment 1715688094
The article you quote is misleading. The LD340 was not updated in the 80's to a spreadbore. It was discontinued and replaced by the Performer (shown in your pic). The Performer and LD340 are not really similar at all.
