310 hp and 320 lb-ft with essentially almost a full point of compression less than the GT350 engine, turning all accessories, doesn't make me feel that bad. Wasn't Hipo/Shelby cam 228° @ .050" as well?
All-in-all, the World heads aren't Dart heads, but we were clueless as to when we'd ever get a set of the new Dart heads in stock, and the customer was eager to get his engine down in his 289 Cobra replica.