Can any one tell me what these two holes are for on a Holley G?
Overflow, I think.
The hole in the bottom is a drain from the spray nozzle area to drain any excess gas in this area. For example if you over prime the engine.
The small hole in the side was added om later Model Gs. I am only guessing that is there to allow any air bubbles to vent back to the fuel bowl. I have two of the earlier carbs and they run great, so I am not sure what problem they were trying to solve.
I had a brass Holley G that had 6 of those small holes drilled around the center. I guess someone added the extras but I don't know why. It ran the same to me.
What I have learned about these holes is this but I am not an expert so others may have other ideas.
First you must remember that the gas they used at that time didn't vaporize the same way as the gas we have now.
The hole in the bottom has two reasons.
- An overflow after priming the cold engine.
- While the engine is running a small quantity of air is going by that hole and a small air stream is created that make the mean stream spinning to get a better air-gas mixture.
The hole at the side make air going in the gas and make it bubble so the gas vaporize easier.
I've always been partial to the Holley G. I find them easiest to work on, properly set up they run great.
Maybe Stan Howe will post and offer an opinion ?
Colin, now I need to go see if my iron G has these holes too and see if they're open.