do a search on timing chain and look for the thread by thomas pindelski. thomas did an excellent picture tutorial on this subject. he estimates based on certain factors when he'll replace his. just seek this out he even has a website he allows you to look at for all his maint work.
1972 350sl Red/Blk 117k
1988 420sel charcoal/Blk 140k
1987 420sel gold/tan 128k
See My Cars at:http://mysite.verizon.net/res0aytj/index.html
Pound it to fit then Paint it to match!
There is only First Place and Varying degrees of last!
Old age and deceit will overcome Youth and Enthusiasm every time!
Putting the square peg in the round hole is not hard... IF you do it fast enough!
Old enough to know better but stupid enough to do it anyway!