+2 on what porkface said. It is a 380 and may still have the single row chain. I think the parts are still available to convert to the double row chain, which I would highly recommend.
By the way, I have worked on a lot of these 116/117 engines and have never seen a 'broken' chain, only broken guides and bent valves. When a guide brakes, the chain gets loose and jumps timing, then that bends the valves and locks up the engine. Most of what I have seen was only exhaust valves bent but no other damage. The worst I have seen was the bent valves along with a hole in a piston and a hole in the cylinder wall.

I would recommend you check for cam timing and if off by more than 5 deg then replace the upper guides and tensioner rail. Then recheck the cam timing again and it should be close to 0 deg. This only takes an hour or 2 and you are good for another 100K or so. If the timing is not off very much but the upper guides are dark brown in color or you know they are over 10 years old then I would replace the guides. If every thing goes good then at the 200K mark I would pull the engine, Remove the front cover, do all guides, chain,oil pump chain and guides, head gaskets, front and read main seals, etc. Then you will be ready for another 100K/200K.

Just my $.02 worth

PaulM

__________________
84 500 SEL (307,xxx miles)