I think in terms of repeatable, you have to remove any other variable than the engine to even consider this. It's all hypothetical, but if you do that, I think the more scienced out engine will be more repeatable. Note I did not say "most hp". I said most scienced out. Because the more "figured out" an engine package is, the less the affects of climate will affect it. If I was building a bracket car, I'd want a pump gas reliable engine. Something that I don't have to open the hood for after the jet change for the weather. If the choices were 408 or 318, I'd go with the 318 because it will last forever. The 408 will need to be freshened fairly quickly comparatively speaking.
