(These odds should update on their own.)
At the time of writing, the -253/+225 line is available at Pinnacle, which does not accept American customers. The readily-available line for those in the States is -275/+215.
Emelianenko is 1-2 in three Strikeforce fights; his losses to Fabricio Werdum and Antonio Silva being the first since the infamous doctor's stoppage loss to Tsuyoshi Kohsaka during a Rings tournament in 2000. The best-available lines on Emelianenko closed at -450 vs. Silva, -480 vs. Werdum, and -505 vs. Brett Rogers.
Henderson is 2-1 in his three Strikeforce bouts, his lone loss coming by decision to Jake Shields at middleweight. He defeated Rafael Cavalcante in March to become Strikeforce's 205-pound champion. The best-available lines on Henderson closed at -128 vs. "Feijao", -250 vs. Renato Sobral, and -340 vs. Jake Shields.
According to SB Nation's Jonathan Snowden, Strikeforce will promote the bout at heavyweight, but both fighters have agreed to a 220-pound catchweight limit.
More SBN Coverage of Strikeforce: Fedor vs. Henderson