If you're just looking for a set of low impedance injectors, generic Bosch fitment around that sort of flow, should be something available in the US ?

55lb is basically 550cc, give or take.

http://www.fiveomotorsport.com/lucas...impedance-3102

http://www.fiveomotorsport.com/10399us580-570/580cc

http://fuelinjectorconnection.com/sh...hp?groupid=102

http://fuelinjectorclinic.com/

http://www.racetronix.com/