So, with the close proximity of that race, Whibley needs to keep a clear head and he will have little time to celebrate his OMA title win.
Whibley (Yamaha YZ450F) will be hoping his final grand national assault is as sweet and rewarding as was his victory at the 10th and final round of the OMA series, the "Moose Run" in Illinois, last weekend.
"I got a good jump off the start line (in Illinois) and rounded the first turn in front, but Adam Bonneur swept round the outside of the wide open corn field, taking the hole shot," Whibley said.
"I moved back into the lead quickly and led the way around the peat bogs, taking safe lines, not wanting to end my race before it had begun.
"I held a small lead as we ventured off the quad track and out into the woods. It is very difficult to maintain a breakaway in this race, as the track is so fresh and you are constantly searching for the arrows.
"Still it was my own personal challenge to see how long I could keep the gap. I made it about half of the 38-mile lap before Jimmy Jarrett and the chasing pack latched back on to me."
To add to the challenge, it then started to rain.
"Midway through the last lap I got stuck in a deep rut and Jimmy Jarrett pulled up and passed me," Whibley said. "I got going again and shortly saw that Jimmy has his own problems with a log, allowing me back into the lead. I again built a gap that I would eventually grow to 1min 30s by the chequered flag."
