As Barry said you can do either. What makes the difference is how much
oil the engine puts up stairs. You can run the
oil pump with a drill and see how much
oil you get up stairs. You can do this with the intake of and the valve train on. If you are getting to much then you may have to restrict up stairs. More than likely you will need at least a .090 restrictor on both sides and we have to go down to a .060 sometimes if getting to much up stairs. It depends on the block and the lifters used.
Thanks, Keith