Holley Mystery With Crappy Pics

[Humboldt Cat]

Set about disassembling the 4160 from Plan 9 for a rebuild (teaching my gf's son Abe how-to), and after removing the secondary fuel bowl, found a "waifer-thin" metering block and a brass-type cover behind it.
Never seen something like in a carb. Anyone know what it is? Should it be removed & cleaned, or leave it be?
It's in the upper right-hand corner. Even under a shop lamp these indoor shots suck.

[Humboldt Cat]

Previous pic was of the brass plate, this one shows the super-thin metering block/plate aside it. I'll try and get better shots tomorrow in daylight. The Argus doesn't have a flash, but that obviously that doesn't stop me from trying...

[Humboldt Cat]

On a side note, finding this sheet metal rocked, today. Sometimes when yer going days with out the sun shining through, it's all about cheap thrills. Anyway, it was a great find, gonna cut out a heat shield for the starter & 390's headers, but who knows after that. Up for suggestion.

[Hot Rod To Hell]

That's the difference between a 4150 and a 4160. Metering blocks VS. metering plates. The metering plates work ok if you get the right one. It will have a number cast into it; any Holley manual can tell you the flow characteristics of it.
YES> remove and clean it! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Deyomatic]

Yep, it's a metering plate, and it is what makes it a 4160, and we just tore one apart two days ago, trying to get all the little pieces that Holley doesn't include in their kit, the screen filter and some new idle screws.