check out fieldsperformance.com, you're not going to find anyone on the west coast that provides the same level of support. mike jr is constantly at the track helping customers with there bikes long after they've paid up. beyond that, i'd challenge you to find a 1397 that runs stronger than what comes out of their shop.
there are tons of good shops that can build you a quality motor, but make sure your builders going to see things through to the end.
good luck!