I used Dolphin gauges on my '50 Chevy too. I took the original gauge housings and cut them out except for the outer ring - some might call it "butchering"
Then I installed the Dolphin gauges into them with the Dolphin mounting hardware. The outer rings from the original gauges act as a bezel for the new Dolphins and they provide the mounting tabs for use in the original locations. It's not an original idea, and it looks like one of the links above might show a similar process. Works good though.
Hope it helps,
Craig
