I bought a kit to rebuild my Stromberg from Mike's Carb Parts and it had everything I needed. I have not had any carbs rebuilt by him so I can't speak to that.
I see he lists a universal replacement carb for a 1904 Holley. It is pricey ($399 on sale), and he also sells kits if you wish to rebuild your own, or he can do it for you.
*There is a section on his webpage that states that there are some items for the carb he does not carry, like the Float. he advises buying another carb for parts.
The carb below has 4.8 rating overall listed on the site. He also has 4 Part series on rebuilding the Holley 1904 on YouTube.
https://www.carburetor-parts.com/190...04_p_3141.html