Best performing small block oil pan?

Stock K frame?
Currently, probably the Kevco, like Rusty said.
All-time best (for bracket racing)?
The Milodon Super Stock 9 quart pan, with some caveats.
First, it's no longer produced. Hasn't been for quite a while now. Still highly sought after, so good luck finding one, and $$ if you do.
Second, it requires it's own specific oil pickup, also unavailable new.
Third, I'm not aware of any version made for the 360, only the 340/318/273. The rear pan seal is the difference (smaller on the 360/Magnums), although I have seen guys make a spacer for the pan and use the 360 rear pan seal. I'm assuming your 408 to be a 360/5.9 based engine.
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This^^^^^^^times 1000.

That pan makes more power and has the best oil control of any pan ever used or seen.

Sadly as you say, it’s no longer made.

That’s the pan I use.