Sound insulation

Hi there guys,

I have a slight luxury problem with my '62 beetle (converted to oval). The 1679 cc engine makes a great sound. But when driving at constant speed on a highway for instance, the sound drives you mad and is loud enough to give you a permanent hearing problem. I there for normally drive with earplugs.

This all is not that suprising since i have no insulation at all. I do have a full interior, but underneath the carpet it's all metal. I did this mainly to save weight. I have no insulation in the engine bay neither.

So what should i add where to reduce engine noise without adding a lot of weight. The 1679 has 40 mm dell's with air cleaners and an A-1 muffler.

The car

The sound system

Hope to get some good input!