I'll vote to make it unanimous - change it. A sloppy timing chain can make the engine hard to start when it's hot. Also, keep in mind that the cam timing is changing back and forth while its running and when the cam moves, so moves the distributor making it impossible to give it a good tuneup. One last thing: In a worst-case scenario, if that sloppy old chain breaks, there's a good chance it will get wadded up between the crank and cam gears and break the block. I saw it happen once back when I was racing stock cars. It broke the crank, the cam, and the front main web in the block.