318 value

Goodie for you.
340s have been scarce around here since the 80s at least. (South Chicago area)
maybe it's location, but there doesn't seem to be a shortage of them here in socal or within a days drive.

and they seem to pop up here almost weekly, in various states of exploded view to complete.

it seems as if you beat the bushes and waive some cash around all of a sudden the parts you were looking for seem to materialize.