Mystery B block intake....

Wrong, wrong wrong. The ch4b small block intakes are all about bottom end. This intake is a DP4B made for B block engines. (350,361,383 and 400) They are not for the RB engines. (413,426 wedge, and 440) These intakes are VERY good street intakes with lots of bottom end and flow to 5500 or so.
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Do you mean the LD4B and the LD 340 small block intakes?
And don't forget the big block 350. It uses the same manifolds as the 361 383 and 400.

U da man Toolmanmike.