Yes, the Viper is an interference engine.
For what its worth, you need to have this engine disassembled and inspected by someone who knows EXACTLY what they are looking at. It sounds like your camshaft is out of time. They do not skip teeth- they break dowels. The question is, WHY did it do that if that is what happened. You may be into damaged cam journal territory, and a locked up or broken camshaft. DO NOT get a non-viper machine shop involved with an issue like this unless you want a headache that never stops. Every single part in the engine should be checked after a failure like this in order to prevent a re-occurrence or a secondary failure resulting from damage inflicted by the first failure.
If you want the problem solved without question marks, we can ship you a crate and have it picked up, and shipped back when done.