GR-4 & GT-4 racers used competition versions of Campagnolos which had thicker mounting flanges, so the wheel studs are longer. How much longer and where one can find them today, dunno. It may be that GT-5 studs are longer, too but I've never checked. Maybe a couple of the big vendors could measure; Les Gray may have a source since he's still restoring his GT-4. If you use real GR-4 parts, $15 ea will likely be a bargain....
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