What are the easiest ways to check for timing chain wear on an 1994 Astro?

I think my timing chain has slipped. It was tuned up yesterday, and the motor mounts were replaced. Any time I put a hard load on it, it'll spit, fart,
pop, or buck. If I'm easy on the gas, it won't hiccup, but it takes awhile to get moving.The distributor shaft(original) had almost no play. The engine has 619,000 km on it, and has been maintained to perfection. Does anyone have any suggestions?
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I likely would have done rebuild/replace at the 500,000km mark regardless of condition, so at 619,000 you should seriously consider it if you can't find any ignition/fuel delivery problems.
Steve
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Mark wrote:

I would start with a compression test. If the chain has slipped then the valves will be opening and closing at the wrong time, which should effect compression.
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You may be surprized to find out you are just running lean, maybe fuel delivery, injector(s), etc. You can check how sloppy the chain is by watching the rotor, turn the crankshaft clockwise till it starts turning, then mark the crank and turn it counter clockwise till the rotor starts turning. See how far it is between start point and where rotor turns when turning clockwise. If it is off 20 degrees the timing will be off half that amount due to chain stretch or 10 degrees. Five degrees of the cam being off would be quite a bit, retarding the cam which loses power, especially at the low end of rpm range. Advancing the cam gives you more torque.

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