Progressive linkage on dual carbs on an inline engine hurts volumetric efficiency (except at WOT) rather than improving V.E.
Think about it. How many Jaguar and Austin Healey 6's with dual (or triple) carbs have you seen with progressive linkage? And the Chevrolet Corvette used solid linkage on the triple Carters in 1953 and 1954.
And while there can be some argument in favor of progressive linkage on a triple 1-barrel set-up on a six; we have had MUCH more positive results with solid linkage even on the triples.
Jon.
