Breaking a timing chain is a pretty rare failure. Skipping the chain is more common, where the cam gets out of time. When that happens you replace the chain and the sprockets. The low-compression 350s are non-interference engines, so if it's a stock engine, no bent valves or pushrods. If it was a high lift engine with domed pistons or high-compression heads or the like, then it can be a different story. But the stock 83 engine is not a problem for interference when the timing chain skips or breaks.