Banana arms, worn track rod ends, dodgy steering pump (if occuiring only on full lock), Fecked spring (only clunking when loaded during corners), fecked bushes.
All or any of the above.
Honestly, you need to get the car jacked up, and the wheel off.
See if there is any excess play in any components, or if anything is obviously broken.
If you don't feel confident in doing that, then take it to a local garage who knows 350's. Where are you based, and someone will recommend somewhere