If all else fails get the welder out...
Hey everyone, on our 1969 (nice) VW Beetle I was having an issue with a popping/clunking sound when going over bumps?. To fix this noise I decided to bolt them in since my aftermarket control arms doesn't have a proper seat to keep the spring held tightly in one place. When I used a pry bar I was able to recreate the sound. I used a bolt in coil mounting kit from Ruff Stuff Specialties found at the link below.
www.ruffstuffspecialties.com/...
Normally these kinds of kits are used on off-road vehicles to keep the springs from becoming loose when the suspension is at max extension but they work great on project cars too.