For what it is worth I went to a Direct Connection seminar at Wise Speed shop in St. Louis in the late 70's Tom Hoover, Lee Shepard, and some guys from Mancini's were there, the question was asked about intakes for street & strip, Edelbrock LD-340 was their pick then. It was mentioned that it made more HP than several single plane intakes available at the time. They also said the factory cast iron intake for 340's with a thermoquad was almost as good as any aftermarket intake at that time.
Bought my blue mopar bible then, still git it.