Holley Double Pumper Question(s)

Mattax said
Good guess but not correct.

-7 is the revision
C is the dichromate finish
The number underneath is the date code.
For example, from the 2018 catalog.
View attachment 1716246254

So either the current revision changed meter blocks etc, or the photo is wrong because the marketing staff is clueless.
My bet is the latter :(

The website info says its an dichromated aluminum body carb with straight boosters. I'm not aware of dichromate finish for aluminum casting as those are usually anodized. Second, the website photo shows downleg boosters. Third there is no mention of four corner idle even though the website photo shows it.

Fair enough it was an assumption on my part and I was wrong.
When probing the hole with a needle it was blocked off. So I think it’s not a marketing issue. I believe this unit is not a 4 corner unit.

Mattax said
Find yourself a used copy of Holley Carburetors and Manifolds by Bill Fisher and Mike Urich, any edition.
You're buying for a good intro into how carbs work and the diagrams, not the marketing content.
Alternatively for less, the smaller Holley Carburetor Handbook, Models 4150 & 4160, Selection, Tuning & Repair
By Mike Urich

Thanks