Rick's advice is basically correct for hot rodded engines. Although many of us bristle at absolute statements like that (and like Don's), for someone publishing to a relatively non-tech audience, its understandable.

SecretChimp has asked the right questions. In a situation where exhaust gas is not clearing out of the combustion chamber (typical with both hot rod and race engines) richer than stock settings get a better burn. Additionally, the relationship between AFR and load is not linear. At low load its a bit richer than stoich, then goes leaner - sometimes leaner than stoich somewheres around 60-80% of max load, then richer again to max load. This is for max power and efficiency as shown in the graphs here.

A really good and detailed explanation of the choice between ported vs. non-ported advance can be found in this wide-band tuning thread starting at post 10 second paragraph & more in post 13. Also check out 'Shrinker' and 'Sasquatch' posts on the next page of that same thread about the history of ported vs non-ported use by the manufacturers.