I'd get a new chain. Those old 4 links will be as worn as the rest of the old chain and are liable to leave you stranded alongside the road. If you really get unlucky, the chain could break and get into your rear wheel, with dire consequences. Chains are cheap, emergency room visits aren't. When you get that new chain, run it around your big ring and largest sprocket cog without putting it through the derailleur. Then drop one full link more and break the chain there. This will make it the perfect length for good shifting. I got this tip from Sheldon Brown. If you ever get a chance, visit his site at www.sheldonbrown.com. There's a wealth of information there, it's one of the best bicycle sources on the internet.

Smokey

Lemond Poprad, Fisher HT mtb, Burley tandem