The LEDs are a definite, brighter improvement. Order the "warm" version. The normal lights are a cool bluish light which I tired of after awhile and changed them to a warm version, closer to OE, while I had to have "Doctor Don" (top flight vintage radio repair service in Texas) repair the radio. And, remember that the instrument cluster will be brighter and nicer than your speedo/tach gauges. Also, you really don't need to replace the warning lights with the more expensive LEDs unless you want to - but, definitely replace them. If you search eBay with a "10x" next to your "warm LED lights - C3 corvette" search, you'll find the best deal on a 10-pack. You can use the remaining lights in your side marker lights. They are not expensive lights these days. While installing, make sure to bend out the contact wires on the bulbs to maximize the positive contact with the printed circuit board. Ask me how I know.
Attached are photos of the back of my C3 instrument cluster to let you count the bulbs on the back. You are wise to do what you are doing while the patient is out and on the table. If your model happens to have a low fuel light, now is the time to replace the module if it is not working (with yellow sticker on mine in the photo). While it is out, you can easily access and lube the climate control mechanisms and such.
Hope this helps. Do the same for someone else. Good luck
Dave
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Lakeside 49
