Trying to find a replacement carburetor for my 66 Valiant

If you need a direct bolt-in, you need a 1bbl carburetor. Since you don't have factory A/C, you need a carburetor equipped for the rod-type throttle linkage.

Tune-up parts and technique suggestions in this thread.

Remember this engine requires periodic valve adjustment

Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.