Small Block Fenderwell Header ID...Anyone Recognize These?

I have these vintage small block fenderwell headers....anyone know what brand they are? Do they fit all A-body cars? I’m guessing with this type of collector they are probably race headers? I didn’t measure the pipes but they are fairly big in diameter compared to my old cyclone ones I have...and they are a longer tube design too. The rear pipe is loose, it slips in at the bottom and somewhat adjustable. They have never been run, used to have a paper tag on each collector but they have mostly worn off and can’t read them, also couldn’t find any stamping or other markings on them. Any help would be great, thanks!!

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