Reply to "Anyone with IR injection run "naked""

Veering-off onto the subject of single plane manifolds, the drawback of single plane/single carburetor manifolds is the 4 short middle runners, and the fact that the runners are not all the same length. Its not an intentional design ... its physically unavoidable. Intake designers try like the dickens to lengthen the short runners. Those short runners kill lower rpm power, they make it difficult to load an engine on a dyno under 4000 rpm. Engines equipped with dual plane manifolds can often be loaded at 2500 rpm, and engines equipped with long runner fuel injection manifolds can be loaded at 2000 rpm, sometimes lower.

The Scott Cook manifold in the picture below represents the current thinking in how to improve the situation. Its pretty tall. Notice that single four barrel manifolds like Scotts have one carburetor butterfly above each "corner pair" of runner inlets, trying to achieve the best fuel distribution possible. The longer runners have less cross-section than the short runners, to best equalize the volumes of all 8 runners.

Long runners of equal length and volume are always the ideal, with one carburetor butterfly hanging above each runner inlet for good fuel distribution. Its where induction systems were progressing in the 1950s & 1960s until such manifolds were outlawed by just about every American race sanctioning organization, including the SCCA. Single four barrel carbs were forced on us, the development of cross-ram manifolds came to a screeching halt since they couldn't be used in racing.

Returning to the subject of IR induction, Kelly is right-on regarding the purpose of the unequal height stacks of the BBC. Again ... the induction system's designer is seeking to equalize induction system length (and volume).