Going to be finally getting around to my timing chain but got a couple questions.
First, do you have to replace the cam and crank keys? Second, I know you have to have the sprockets lined up by the marks which would indicate TDC, but how does one go about turning the cam and crank to facilitate this?

 

You do not need to change the cam or the key.

Just take your old gears after you have removed the chain and turn the cam till the mark is at 6 o'clock. Then turn your crank till it is at 12 o'clock.

Set the new gears on a table with the mark aligned the correct way and put the chain on. The. Install on the truck. Make sure keep the correct alignment as you install.

 

I haven't read of folks here changing the keys. I've always replaced keys when doing repairs when replacements readily available.
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^Good save.

 

The question is how/easiest way to do this so the marks are lined up prior to gear removal so new ones can be slapped back on.

Experts here?
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By keeping the chain on. Remove the spark plugs and rotate the motor by hand until the marks are at 12 on crank and 6 on cam. Remove the entire assembly without disturbing the positions of the crank and cam. When you refit make damn sure nothing has rotated. If you really want to get all waded up about interference remove the rocker assemblies because you will get some minor rotation by the cam with the lifters being in contact with the cam, it's inevitable so follow the Rave for reinstalling.... you have a bit of wiggle room to adjust the gears back into 12 and 6 before reinstalling the whole enchilada. You don't want full rotations of either stick.

 

 

Keys and keyways become soft edged. What you don't want is a key to roll or split. Replacing is always a good thing.

 

Well if its a 4.0 or 4.6 it wll only have a woodruff key in the crankshaft, the cam gear had it cast in. Crankshaft keyway is pretty long. Never noticed any deformation on them. I think youll do more harm than good replacing it