I'm building a 406. I am using a gear drive. do i have to use the cam button? thanks

If its a roller cam, you will need a button or some type of retainer or the cam will walk. On the Summit page ,the Pete Jackson kit comes with a button.

If you are using a roller, you will need a thrust bearing and a cam buttion to prevent cam walk/play

If you are using the gear drive, you ALWAYS need a cam button, there's nothing to keep it from walking forward otherwise. (like a chain)

I forgot to elaborate I have a hyd.cam 284-h (thanks tommy).I have a pro form noisy gear drive. I have the pro form engine dress up kit and don't want to mess up the timing cover The cam button has the roller bearings in the middle but would the neoprene cam button work better for the aftermarket cover? I dont want a hole in it. Thanks .

Either would work, we prefer to use the roller style bearing. If it is the correct depth for the cover there shouldn't be any wear issue. The lifters will do the bulk of the cam retention, with the button taking up the balance of the movement.