[markjohnson]

It's kinda hard to tell from a photo but it does kinda look like they do have some port work done. Your intake ports look pretty smooth and don't have that rough "as-cast" texture to them. Intake ports should be pretty much exactly the same between 840's and 291's but 291's are slightly superior because of their 1.88 exhaust valves while 840's only have the 1.72 exhaust valves. But hey . . . . . since the valves are out, just stick your finger in the valve hole and feel the short short side radius (the floor of the port), if you can feel a sharp edge just a little ways down from the valve seat than they probably have not been ported. If the port floor feels smooth without the sharp edge than they've probably had at least a little port work done.