I recently had my ford 4.0L gone down on me. One of the cassette at front timing chain broke and a guide I think. My question is how would I know if I bent a valve when this happened??? How do I check to make sure??

 

The valve stem may be bent in a manner which, when closed, leaves it "not as high" as the others in its plane. Remove the valve cover to examine.
Also, you could remove all 6 spark plugs, turn the engine by hand and blow air into each cylinder when it's supposed to be on compression stroke.
You'll be able to hear escaping air at the throttle body or tail pipe.

You could use a borescope through the spark plug holes to check visually.

One fellow here stated his preference for the OHV 4.0l over the 4.0l SOHC for occurrences such as these. He thought the hp increase wasn't worth the fragility.

 

What's the odds that it did bend a valve?? Is it common for this engine to bend a valve when something like this happens??

 

It is an interference engine. I've no damage occurrence experience.