Question about timing chain and gears

I have a 1997 C1500 305 with 144000 miles. question is, when sould i change the chain and gears ? Or when does GM recommend them be replaced. I know it sounds like a dumb question but Im sure that the wear on the chain and gears will cause performance issues. Or does the PCM/ECM compensate for timing chain/gear
wear in corallation with the crank and cam sensor?
Thanks in advance,Ron

Thanks for the insight guys. and all who helped..

Thanks for the insight guys. and all who helped..

I do not think they recommend chaing them.
Timing chain and gears do not wear much on the GM V6 or V8 engines.
To check for wear or slack rotate the engine back and forward by hand and you can feel slack.

Or to check for true valve /chaing timing the No 4 cyl valves will be rocking when no 1 cyl is on TDC comperssion stroke.

Let us know how much slack you have.

Thanks MT for the reply, I will try that this weekend and report back.What in your opinion would be to much play?