Information from Mike Kleinow on the Holley 780 Carburetor
"I pulled my NOS 780 Holley from it's box and here's what it says on the front right of the choke horn.
D1ZZ-9510-YA LIST-6127 272
The Motorcraft tag attached to the choke housing is stamped D1ZF YA A and 2G1 under the YA portion
The ink stamping on the primary fuel bowl reads 6349N with a "4" ink stamped by the upper right screw on the top of the bowl.
The ink stamping on the secondary fuel bowl reads 4845N4
The ink stamping on the vacuum secondary housing reads 865N.
The stamping on the fuel filter reads AUTOLITE C9AE9155A
It has a 30cc Accelerator pump mounted on the primary fuel bowl, and no accelerator pump mounted on the secondary fuel bowl.
The accelerator pump cam is white and mounted in the '2' position.
This carb has never had fuel in it and was placed on an engine only once for a show, and then taken off. There are some marks at the mouting holes because the idiot didn't put washers under the nuts!
Anyway, I'm wrapping it back into it's plastic and putting it back into the box.
The markings on the box reads
ONE CA-879 D1ZZ-9510-Y CARB. ASSY. WITH GASKET
Hope this helps.