Well since I've had it the engine has run faultlessly and the belts were done 8k ago, so if the timing was incorrect I'm pretty sure it would have let go a lot sooner. If you look closely on the picture '3' of the 2 valve stems , the one on the right you can see at the bottom of valve stem there is a slight colour change that's where the 2 piece valves are friction welded together. Having one piece valves would eliminate that weak spot.