The box is all I have to go by and trust...Note the serial # on the box and the serial # on top of the engine...They match...Click on the blue box in the lower right corner of the pic to enlarge the pic...You can read the #'s easier with the pics enlarged...

I think that there is no exact science when it comes to these Quadra engines as I've heard so many different ways to identify them...Again, the box and the matching serial #'s are all I have to go by......

Kevin