You aren't likely to find that exact 1975 carb without a long wait. First couple years of Holley 1945 (1974, 1975) were problematic anyhow; later ones were markedly better.
"Remanufactured" carbs are junk. Two good, fully-compatible, new carbs:
this and
this.
While you're at it, see tune-up parts and technique suggestions in
this post. And Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted
here for free download.