What's your opinion on the slack in this 318 timing chain?

There is probably nothing wrong with yours if the slack is less than a half inch...

copy and pasted from the web:

The proper way to do that would be with the timing chain cover off. Essentially you're supposed to put a straight edge across the gears and measure the slack in the chain by pushing on it to see how much deflection there is from the staright edge.

You can stick your finger in the fuel pump hole and push on the chain but you really can't measure the actual deflection. The best you can do is get a ballpark guess from what you feel.

You need to make sure all of the chain slack is on the fuel pump side before taking he measurement. You may have to put a socket on the big honkin' nut on the crank and turn the engine a bit (counterclockwise I think) by hand to do this.

The shop manual says that if there is more than 1/2 inch in deflection in the chain then it should be replaced. If the chain is really loose you might be able to feel it out through the oil pump hole.