Dual quads versus big hammer!!!...

Then look like fuel baffles, in the fuel bowl........do you think you are dealing with fuel slash?.
I know you said it would launch just fine. but you said something about leaning idle mixture screw and a.......rough idle when stopping or something like that.

Just wondering if you might want to keep them. One of your carbs may not have had them installed from the factory...............

don't think this would have anything to do with you cruising/tip in stumble.
When I talk to the Holley techline kid this morning he said the reason the last guy probably sent the wrong part was he didn't look into the blueprints of the carburetor. He just seen what looked like an air baffle. The guy took a lot longer and had me on hold for quite a few minutes searching for the correct part. So yeah that are baffle has nothing to do with what I'm looking to try. I'll post another picture here real quick and maybe the link if I can find it to get you up to speed but it's probably in the first page or two of this thread..Screenshot_20200304-075024.png