If anyone has one, or have pictures of, I have two questions.

1) Is the fuel bowl sight plug mounted high, like the center carb, or lower like the #4790 rear carb?

2) Does the booster venture have the distribution tab on the passenger booster just like the #4790 rear carb?

Thanks.

Both front and rear have the tabs,sight plugs are only high on the center bowl,all applications.

On my #4789 front carb, the bowl has the high sight plug, like the center carb. Do you think that someone changed it? Why are the sight plugs lower on at least the #4790 rear carb?

Also there has to be at least one small difference between the #4789 front and the #4790 rear carb for Holley to bother making them two different part numbers. I was just wondering if it was the fuel bowl that are different.

`Here is a pair,4789/90 that have never been apart,some of the early 4391/92 (A12) carbs had no bowl vent and the high sight plug as the balance of center carbs.All dual inlet four barrels used the same front bowl with the high plug so it is not uncommon to find those bowls on 2300 series carbs.As for the numbering on the end carbs,the main bodies are identical.

Thank you very much for the picture and the info.
Now, Nobody seems to know of any reason why Holley had a separate part number for the front and rear carbs.

Also, why do the front and rear carbs have that lower sight plug?

Thanks.