what are the general problems and wear & tear with a 340

Rust, carb (warping, getting loose, getting worn), bad service history, fuel hoses leaks.

Rust causes load of problems, struts need repairing in many cars because of it, also at least in 360 part that holds gearbox on place is often rotten away, bottom of doors are often non existent etc.

Strut top mounts also can be cracked and then steering is really heavy. Gear linkage can be loose from mounting point (mostly in 360).

Many things are related to bad maintaince.

A general browse of the forum would give you a good idea of the common problems.