My car has 100K miles on it, I'am going to replace the timing chain.
Should I replace the valve springs also?
If so what springs? Can you still get the GM springs from a dealer?
The car runs 13.20's and has no sign of weak springs (105-106mph)
a lot of vendors like cottons and kirban for example sell valvesprings for about $45. my theory is "if it aint broke dont fix it" try testing your springs first before you go replacing them.
Replace them! 100,000 miles they are worn out. I replaced mine at just under 100,000 and picked up 2-3 tenths at the track. I got mine from Kirban's with the tool. Not very hard, just takes time.