I'm in the same boat, I ordered a F50 (47cc) kit from thatsdax and it came in a box marked F80. I wanted the F50 because I had read that they ran smoother and started easyer with not that much of a power differance. I was so excited when my kit came I just tore it open and started checking out all the cool stuff in the box. Anyways I didn't notice the fact that the box was marked in big letters on one end F80 for about a month after I had it installed and running. So I have no idea if its a F50 or a F80. It starts easy and seems to run smooth but I have nothing to compare it with. It would be nice to know when ordering parts. I never called Dax to complane because I'm happy with it and I'm not giving it back. It's kinda like having a new puppy you get attached to it.