Voters in Manassas Park will choose between two incumbents and two city council members when they pull the levers for commissioner of the revenue and treasurer on Nov. 5.

Norma (Betty) Mullins, 51, serving her seventh year as revenue chief, will face 57-year-old council member Frances Embrey. Ron Smith, 47, serving a four-year term as treasurer, will be opposed by 50-year-old council member Dorothy Bello.

The efficiency of the office is at issue in the race for commissioner of the revenue, focusing particularly on whether two full-time clerks are needed to help the revenue chief do her job. Last October the Prince William Circuit Court decided that the cities must meet the State Compensation Board's requirement that Manassas Park allow Mullins to hire a second full-time clerk. Mullins said at the time that she believed the opposition to the clerk, whom she said she needed to run her office efficiently, was mainly due to the fact that she (Mullins) is a Democrat. The city administration is mostly Republican.

Embrey, who is running as an Independent, has served on the City Council since 1977. She said she will return the commissioner's office to one full-time and one part-time clerk if she is elected. "That office can be run more efficiently with less help," she said.

Embrey believes that buildings under construction at Conner Center, the city's industrial park, are not going on the tax rolls fast enough. She would, she said, get them on the rolls quickly and reduce the property tax rate, which at $2.43 per $100 of assessed value is the highest in Northern Virginia.

Said Mullins, "We go out of our way to help the taxpayers in this office. I want to continue doing that."

Smith, who is running as an independent, has held the treasurer post for three years. He described the campaign as a "fairly clean" one and said he intends to talk to every one of the city's 2,000 residents in his door-to-door campaign. He cited his seven years of bookkeeping experience before winning the treasurer's position in a special election as a necessary background for the job. <

In addition, his office has been assertive in collecting delinquent personal property taxes, garnering $80,000 since 1982.

Bello, a Republican, said her four years on the city council plus her service on the planning commission prior to her election in 1981 have given her not only sufficient budget experience to do the job but also the advantage of knowing what the council wants out of the treasurer's office. Bello, who earns $2,000 a year on the council, said she would use the $27,000-a-year post to make the treasurer's office "more accessible" to the people by keeping it open one evening a week.