That's not really how it works....
Modern engines, my foot. (other than that, DemonX2 is 100% right).
The key was never designed to carry load, ever.
The sprocket bolt that clamps the cam sprocket to the cam is what makes the spinny-magic happen. The clamp load from sprocket to cam is what locks the two together. I ain't doing the math but there's hundreds of pounds of force holding the cam to the sprocket when the bolt is properly torqued.
The keys are supposed to be weak. If something goes south, the intent is to shear the key and not eat up the nice expensive components (although on a small block Mopar you're likely going to trash the valves if this happens).
The key is an alignment aid only and carries no, I repeat NO load.