The 50th season of AMA Pro Motocross is now just three days away. And what better season is there for arguably the most stacked 450 class in the history of the sport. No Jeffrey Herlings, but there is a total of 16 AMA/FIM Motocross Championships represented in this group. Most notably the all-time KTM duo of the returning Ryan Dungey, and MXGP icon Antonio Cairoli. Additionally, reigning champion Dylan Ferrandis, Eli Tomac, Ken Roczen, Chase Sexton, and Christian Craig all look to ascend to the top of the mountain. Headlining this preview of the 450 AMA Motocross class will be Honda HRC, Rock…