Sun actually did make black painted cups for blue and green line 2 5/8" gauges. I have a couple of them NOS. GCB-1
If you have any rusted chrome cups, they can easily be stripped and then painted or powder coated. I like chrome myself.
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Here's a shot of my Nova back in the late 70's. I had 5 gauges and a MOROSO Tach on the dash and the FUEL PRESSURE outside !!!!
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