Whether you replace the timing chain or not, I'd recommend upgrading the front crankshaft seal to a lip seal. Details here:
https://www.pontiacsafari.com/L1Gara...ealUpgrade.pdf
I still have the alignment/installation tool that I had made when I did mine. I'll loan it out with a $100 deposit, gladly refunded when the tool is returned. You pay shipping both ways. You'll be around the 14th user.
Just remembered you are in Europe. It would probably be cheaper to have a machinist make the alignment tool than to send it across the Atlantic twice. One of the Pontiac guys had his machinist make one from some kind of plastic. I'll see if I can dig up the details.