I believe an 83 would have a single row timing chain. Cost of converversion to the double row chain was about $2500 when I priced it about a year ago when I was drooling over a 380SLC.
2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg
And remember folks, Only You Can Prevent Hilliary.