At times manufacturers blessed cars and trucks with instrument panels that rival fine clocks. The trouble is that many of these panels were developed in the automobile's adolescence when things like an engine's vital signs hardly factored. The low state of tune at the time meant that oil pressure and water temperature gauges rarely read any more than high or low or hot or cold, and even rarer did they do that very accurately.
Modern engines or early ones tuned for more output usually operate in ranges that far exceed those original gauges' capacity. Nowadays companies specialize in retrofitting old gauges with modern movements and re-screen their faces with modern scales but not even that is without flaws. The inexpensive retrofits pierce the veil of suspended disbelief (they look obvious) and the faithful looking ones often cost thousands of dollars. And for good reason, quality is expensive.
We swear we're not bashing retrofits but they fall short in another very critical cultural way that no money can address. During the Golden Age of the hot rod and custom car nobody ever dreamed of retrofitting an old gauge with a new movement and scale. They resorted to the familiar and more often than not they hung mass-produced accessory panels below their dashes and filled them with aftermarket gauges. So from a historical perspective a car built to appear as if it was a hot rod for 60 years isn't authentic unless it has at least a few aftermarket gauges in a panel under the dash.
Of course that isn't without flaw either. We've grown far more discerning over the years. Even when we faithfully build a vintage-themed hot rod or custom we do it to a far finer degree than our forebears ever did. So in an ironic twist, a mass-produced accessory panel hanging from a dash of a really high-quality car pierces the veil of suspended disbelief. Suddenly something that's so faithful to the past looks oddly cheap and out of place. Sigh.
This is where a really creative person will observe that it's not necessarily the idea of a panel that fails as much as what that panel represents. Mass-produced accessory gauge panels look out of place because they look too undifferentiated. They rarely fit because they look as if someone bought a part anyone else could buy and bolted it to a very specialized vehicle.
But if you build a gauge panel with the same passion and style that built the rest of the car then it will magically take on an air of authority. Bear in mind that building a part with the same passion and style as the rest of the car doesn't necessarily translate to trying to make it appear as if it's a factory part. That would defeat the whole idea of an accessory panel and gauges. And it would be dishonest: We've seen dashes enough times to know when something is out of place. There's a fine line between a handcrafted part and an imposter.