Blue Thunder Dual Plane Intake with Different Plenum Divider and Spacer Combinations

When our 492" FE first went on the dyno, we were keen to use a dual plane intake manifold if possible, to maintain the sleeper appearance of the engine. As a result we tried to optimize the plenum configuration of this intake. The original plenum divider was cut out of this intake, and the plenum slotted so that a 1/8" aluminum plate could be installed to replace the plenum divider. Several versions of these plates were made up, cut down to different heights, for test purposes. In addition a 1/2" open spacer was on hand to experiment with.

In the end cutting the plenum divider down by 1" and adding the 1/2" open spacer gave us a big power gain over the factory plenum and no spacer. But then a switch to the Victor picked up 40 horsepower, so we abandoned the idea of running the dual plane intake.

492" FE Plenum Mods on Blue Thunder Intake