Westech in Mira Loma is a good place to go. Steve Brule is a damn sharp fella and have always been very pleased doing business with him.
You can bring your headers... but they have headers with o2's and egts that work with their exhaust system. They have a digital 7 box for ignition and enough fuel pump to feed damn near anything. You just need your motor carb to pan... balancer to flywheel... and distributor, plug wires, etc...