Took my '76 to the local PCA "People's Choice" concours last summer, out of 3 teeners there, mine came in behind a ratty '72 with body rust, big paint scratches, and gutted seats. Had to be the bumpers
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Was inclined to keep the big bumpers for the safety aspect as Dave mentioned, but when those SUV trailer hitches are at eye level, I just don't think the bumpers are gonna matter much, so I'll probably switch to the shiny ones eventually.