[CSX 4027]

First, I have seen engine builders with real conservative dyno's and no bull.

Second, A dyno is a must!!!! Yes.. It is the cheapest insurance(no sales pitch leenie) for both you and the engine builder that the motor works well.

Also, It is a great tuning tool to get optimum if that's what you want but.......
Ask a builder what was the most he ever got as an increase from the first few baseline pulls to the super tuned tweaked pulls. It ain't 100hp I can assure you. Most times would be hard pressed at 20 to 25.