The race has implications for current office-holders, with Gabrielson on record as opposing the state's two most high-profile Republicans Sen. Orrin Hatch and Gov. Gary Herbert.
Sources close to Hatch and Herbert say they are not taking sides in the race. They are sending a joint letter urging delegates to attend the convention on Saturday. While pundits believe a higher delegate turnout will favor Evans, the sources say it is common for elected leaders to send such a letter.
Gabrielson in 2010 posted comments on a popular conservative blog stating that "Hatch is going down" in 2012. He was the Wasatch County chairman for Morgan Philpot's congressional campaign in 2010 and was Philpot's ally when he challenged Herbert for the gubernatorial nomination in 2012.
Gabrielson has been endorsed by former State Sen. Dan Liljenquist, who challenged Hatch for the nomination in 2012, as well as Philpot, Sen. Mike Lee and Rep. Jason Chaffetz.
FreedomWorks is a deep-pocket PAC that has claimed responsibility for ousting Republican incumbents it deemed not conservative enough, including former Sen. Bob Bennett, who was replaced by Lee.
The PAC has ties to the Gabrielson campaign. Several FreedomWorks strategists are helping Gabrielson.
FreedomWorks also worked mightily to unseat Hatch last year, although he outsmarted the PAC at its own ground game of stacking the neighborhood caucuses to elect friendly delegates.
That's why a large turnout might aid Evans, as the same delegates who were Hatch recruits in 2012 will be voting for the chairman in the organizing convention this year.
Both sides, behind the scenes, are pointing out weaknesses in the other with the Evans campaign noting Gabrielson's inexperience. He is in his first term as Wasatch County chairman.
The Gabrielson camp points to a checkered record for Evans in getting Republicans elected when he was Salt Lake County chairman. The County Council went from a Republican to Democratic majority on his watch, and longtime Republican Sheriff Aaron Kennard lost to Democrat Jim Winder.
But Evans' supporters say he staved off potential big losses in Salt Lake County legislative races in 2008 when presidential candidate Barack Obama carried the county.
A Gabrielson flier has been chided by his detractors because it says that under his watch, the Republicans got more votes than Democratic Rep. Jim Matheson for the first time ever in Wasatch County. But in 2012, with Gabrielson in his second term as chairman, Matheson was not on the ballot in Wasatch County because redistricting took that area out of his district.
Gabrielson's defenders say he was talking about being Philpot's county chairman in 2010, when Philpot got more Wasatch County votes.