I found this:
The Holley model 1904 carb, with a "Vis-A-Bowl" is pretty much identical throughout it's usage "era". The bowl will go on all 1904, 1908, 1909, and even 1920 carbs, as long as you have the glass bowl only hardware.
There are differences in the glass casting, but those are cosmetic. I've seen bowls with no script, bowls with a "Holley" script in block lettering in the lower left corner, and the more rare large, tapered "Holley" script across the front of the bowl. You can, if needed, replace the glass bowl with the metal bowl, and all you'd need are the correct screws (& bowl) to fasten the bowl to the main body.
