parts interchangeability ??

Your initial question is ill-posed, hence little response. 1963-66 A's are nominally the same, but important differences (some mentioned). 1967+ are very different.

V-8's started in 1964. The cable-shift disappeared in 1966. 1965 did not have push-button shift, but did have the same 1963-64 transmission, but some say the 1965 valve body is unique. Fitting a small-block V-8 into a 1963 takes more work since the factory distributor bumps into the firewall bulge. I think some have fit even a big-block into 1962-63 A's, but I am sure much customization, and those are mostly drag-race only. Even changing from slant to small-block in a 1964-65 requires many changes (steering linkage, ...).