Both Clark and Eagar have believed from the beginning that the crowded race for the open 2nd District seat would go to a primary rather than being resolved Saturday at the State Republican Party Convention.
"We're anticipating a primary, and we're anticipating we'll be in the middle of it," Clark said.
Eagar said the numbers were encouraging.
"There are a high count of undecided delegate voters and primary voters, and anything can happen between now and Saturday," she said. "But it [18 percent] looks good for the primary."
There are 11 candidates vying for the GOP nomination in the seat now held by Democratic Rep. Jim Matheson. The lone Democrat representing Utah in Congress has decided to run in the newly created 4th Congressional District after the 2nd District was dramatically changed in the recent redistricting.
The Tribune poll listed eight in the poll (eliminating the lesser-known hopefuls), but only five managed to pick up support in the poll and just seven have reported contributions to the Federal Election Commission.
Among those FEC filings, Eagar has raised the most to date with $201,849, while Clark reported $134,837 in receipts.
Chris Stewart finished third in the poll with 11 percent, while Howard Wallack and Jason Buck finished several percentage points behind Stewart. However, according to the latest FEC filings, Wallack has raised slightly more money to date than Stewart $125,528 to $111,883.
Stewart said it was "great news" to be in the top three of the poll.
"We really, truly have positioned ourselves for a primary race," Stewart said. "We entered the race late and, given I'd never run for office before, I think that's great for us to be in that position with the top candidates."
But Quin Monson, political science professor at Brigham Young University, said the numbers mostly reflect name recognition among a larger pool of potential voters who aren't necessarily paying attention to the race, but rather the actual outcome of the convention and that there "isn't a clear favorite" in the race.
Clark was Utah House speaker from 2008 to 2010, and Eagar made a run at the U.S. Senate seat eventually won by Sen. Mike Lee in 2010.
Monson said, however, the speeches given by the candidates at the convention could be one of the biggest movers for delegates and that the final tally between the top two vote-getters would be a signal to primary voters.
"If it's 58 percent to 42 percent, the person who got 58 is in a better position because there is a bit of credibility of getting the endorsement of a solid number of delegates," Monson said.
With such a crowded field, Monson said it could also come down to little things that differentiate the candidates from each other since they are largely in agreement as Republicans on core issues.
He said those factors could be anything from the professionalism of mailers to how credible the candidates present themselves at delegate meetings and, ultimately, at the convention.
Washington resident Barbara Anderson, who was a participant in the poll, said she's supporting Eagar because she would like to see some gender diversity in the Utah delegation. Currently, all five delegation members are male.
"You do realize there aren't very many [women] in offices, and so I decided to pick her," Anderson said. "I'd like to have more representation than just the good old boys' club."
But Salt Lake City resident Jim Stice said he's undecided on the field.
"I'm looking for someone who can reach across the aisle and not drink so much Kool-Aid," Stice said. "It seems folks on both ends are stuck on ideology."
The poll was conducted by Mason-Dixon Polling & Research, Inc. for The Tribune, and polling occurred between April 9 and 12 among likely Republican voters.