89 G20 van with 5.7tbi, timing chain question

I just bought an 89 G20 van with 109k on it.  Any idea how long the typical timing chain and gears last on this motor??  Anything else I should change before it breaks? head gaskets?
tks,
nitro

its really hard to tell because you never know how that engine was ran. best thing to do is remove the cover and see how much slack on the chain there is. if in doubt of its condition just replace it.