Carb tuning, larger accelerator pump nozzle?

Most of the good older Holleys had two holes per channel, each around .026 to .028"
If you're doing three, then they need to be smaller.


I have two pin vises, or maybe three I forget.
One for hand held and the other for holding in a jacobs chuck.
I assume you are drilling brass screws? (as opposed to some sort of plug inthe blocks).
For the set screws I put the set screw in the chuck of a drill I can run real slow. The drill bit (in the pin vise) is in my hand.
I usually bring the bit in on the hex end.
All of the traditionally trained machineists and techs I've known use nose grease (yea. snot). Being a kid with a degree (a degree of what I dunno) I've experimented with WD40 and such. LOL. When the tip of the bit starts cutting you'll know it. Yup not too much pressure, it won't cut when bent. LOL

I'll see if I have any photos.

Thanks. I'm happy to plug one of the emulsion holes, they are threaded.

Set screws were brass hex, 1/8" long. I made a fixture from a scrap piece of 1" square 6061 aluminum to thread the set screws in with a thru hole on the back side so chips would fall through and the bit not hit a hard surface. Hand drilling worked best. I did it dry so I can feel the grab. Risky but it worked out.