I drove with open headers on 468 bbc with a tiny blower. I got tired of it relatively quickly. But a set of cheaper glass packs did not make it sound any quieter. Borla or magnaflow or a set of turbo mufflers would be my vote. Had a set of turbo mufflers on the TA a while back and they were relatively low in noise at idle but opened up at full throttle.
Open exhaust on a 5.3 was relatively loud as well, but nowhere close to the old big block
open exhaust on stock 5.3ls:
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open exhaust on stock 5.7ls:
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glass packs on a big block(very old poor phone recording):
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had a video of turbo mufflers somewhere but it is lost for now