Personally, I don't like changing cam timing with the crank sprocket. I do like the JP/Rollmaster timing sets, but the crank sprocket fits extremely tight to the crank. It is very hard to get on and off, unless the ID of the sprocket is "honed "out a little bit. The reason I like the cam bushing better. You need to remove the cam sprocket and timing chain to be able to remove the crank sprocket and change the keyway, then you need to use a puller/installer to R&R the crank sprocket. Why do the extra step of removing the crank sprocket, when the cam sprocket is already off. Just change the bushing.