The boys at the Wheeler-Evans Elevator Co. in the heart of the Texas Panhandle wheat country voted overwhelmingly for Ronald Reagan two years ago and now are optimistic about the prospect of increased grain sales to Russia.

But the president, seeking farm votes by opening the door for more Soviet wheat and corn purchases, shouldn't be mistaken about the political intentions of the Panhandle farmers on Nov. 2. They say they have no intention of turning against their Democratic congressman, Rep. Jack Hightower, who has represented this 400-mile-wide Bible Belt expanse of flat plains, unremitting winds and towering grain elevators for four terms.

They see Hightower as one of them, a conservative whose consistent and predictable dedication to farm interests outweighs the claims of his challenger, Amarillo businessman Ron Slover, who promises a more consistent and predictable dedication to conservatism if elected.

In 1980, Slover latched on to Reagan's coattails and gave Hightower his closest race, losing by a 55-45 percentage margin. The odds against Slover look longer this year.

Raymond Blodgett, a stocky, round-faced man who farms 4,000 acres of wheat and grain sorghum, jumped on the Reagan bandwagon when President Carter imposed his 1980 embargo on grain sales to Russia. The 55-year-old Blodgett says he is not disillusioned with Reagan, despite the continuing depressed farm market prices.

"I haven't given up on him yet," Blodgett says of Reagan. "His programs are getting inflation under control."

But Blodgett says that does not mean that he's going to vote for Slover, for whom three administration surrogates, including Secretary of Energy James B. Edwards, have come into the district.

"You can talk to Hightower," says Blodgett. "He understands the farm problems I have."

Adds Owen W. Lafferty, the manager of the grain elevator, "Hightower is still the best guy for our area. Occasionally he votes for liberal bills, but we realize he's got to scratch their backs to get what he wants. He may not be able to do everything, but he knows what's best for farmers."

The 56-year-old Hightower, an amiable but otherwise colorless campaigner, is one of the so-called Boll Weevils, the conservative southern Democrats who generally voted for Reagan's economic program.

He also was a cosponsor of the proposed Farm Crisis Act, which would have boosted farm price supports. It was torpedoed in a House committee, Hightower says, when three Republican cosponsors of the measure turned against it under pressure from the administraton.

Slover says his organization's polling shows that Hightower has declined in popularity over the last two years, but still enjoys a 4-to-1 favorable rating in the district.

Despite Hightower's record, the 45-year-old Slover, a jut-jawed financial planning consultant, thinks High-tower's support for conservative and farm positions is tepid at best.

He regularly chides Hightower for getting off the House Agriculture Committee "to go to the bottom 10 percent in seniority on Appropriations." (Hightower is the 23rd ranking Democrat out of 32.)

"We've got to find some manner to reduce the total production of grain" to boost market prices, Slover says, while conceding he hasn't "figured out the answer how to get it done."

Slover says that "by far" he would be more consistently conservative than Hightower. "The district wants a conservative that's somewhat predictable."

Hightower scoffs at this.

"He makes a great deal that I've not been a 100-percent Reagan supporter," Hightower says. "I'm a Boll Weevil by definition and association. . . . I'm not a 100-percenter. I still try to to examine the legislation and represent my district."