i was told by mike at" MRL performance.com" that the biggest problem with the 6pack set up was the intake manifold(tested cars and dynoed engines for ma mopar) .i personally havent used the set up, i would sure hope that a 500+cube engine would pull great #with or with out a 6 pack on it . why not fuelinjection? you get every thing milage , performance ect all in one for about the same $ BUT it doesnt look as cool as a 6pack does i do agree. imop Bill