Frustration: finding out that the equal-to-within-one-RCH, perfect fit and radius set you made produces 5 hp less than the coat-hangar J. C. Whitney setup your friend has. 50 years ago Mickey Thompson did a demo in which he heated up the primaries with the engine running, and pulled them up and out 60 degrees. Result: +50 hp.

It's not science yet, there's too much random and unknown to know what works. Read Gordon Blair on exactly how many waves are present inside the primary = there's constant traffic in both directions.