I have one and it's a nice engine but I have to tell you it's the biggest pain to mount right. All rear carb engines require a hole in the firewall but the 80xi requires a hole that puts it so close to the mounting holes even using the 3W plate that you have to grind off the side of the standoffs to clear it. That and the carb block, carb, and velocity stack stick way back there - you have to make room for it.