I think it was Sissel that used to sell a complete modified head called the "Lions Share Head", meaning that an economy port job was done that got you 80% of the way to a completely ported and polished head. Unstated in the ad was that the "lions share" of the benefits can be attained with only minimal work - deburring, minor blending, gasket trimming and a good 3-angle valve job.
Food for thought.
