So I could take an a/c bracket off of a '69 Polara and throw it on a 340?Yes. Most non magnum small block parts are inter changable.
as far as internals i know that 1972 and up 318/ 340's do share the same cast crank.
:read2:Here's a question for you guys? Is the forged cranK in the 273's the identical crank in the early 340's? Did all 273's have a forged crank?