Alan Levey, the eternally optimistic head of the Maryland Republican party, predicts GOP money plus appealing black candidates could add up to gains for both Maryland minorities at the polls next year, but so far he's had limited success in selling that political equation.

In Prince George's County and in Baltimore, Levey said, population shifts are providing both blacks and Republicans an opportunity to win some offices now held by white Democrats.

Redistricting plans currently under consideration would create two black-majority state legislative districts in Prince George's and would leave Democrat Steny Hoyer seeking re-election in a congressional district with 40 percent minority voters. Levey said black candidates could win all three of those posts, and, if those blacks were Republicans, his party could break into the all-Democratic Prince George's legislative delegation and pick up another seat in the U.S. House of Representatives.

To that end, state Republicans have been negotiating with the Rev. Perry Smith, a prominent black Prince George's minister, who has already been laying the groundwork for a challenge to Hoyer. Smith is a Democrat, but Republicans would like to see him make that race on the GOP ticket.

After three weeks of overtures, including pledges of substantial GOP financial support for a congressional campaign, Smith, pastor of the First Baptist Church of North Brentwood, said he is encouraged but not ready to join the party of Lincoln just yet.

His reticence is an example of the uphill battle the Maryland Republican party faces in convincing blacks that it is serious about them. Even Levey, tantalized by the possibility of a successful black/Republican coalition, acknowledged that in the past "there has never been much opportunity for blacks to get ahead in the Repubican party in Maryland. We have to show blacks that we want them as Republicans and we'll help them get elected."

Perhaps the best known black Republican in Maryland was Dr. Aris T. Allen, an Annapolis physician and one-time state senator who gained national prominence at the 1980 Republican National Convention.

Allen recently resigned from the state Senate to become director of the health standards and quality bureau in the Health Care Financing Administration of the Department of Health and Human Services. Allen declined comment on the future of blacks in Maryland's Republican party, citing the legal prohibitions against partisan political activity by federal employes.

Barbara Anderson, chairman of the county's Republican central committee also talked to Smith last Friday about running as a Republican. "The central committee has a policy of not endorsing candidates before the primary, but we would certainly welcome him into the party," Anderson said.

"It's not that we're pinpointing black candidates; we're encouraging them. There is a sizable number of black candidates among the county's 55,000 Republicans. Certainly the majority are white, as the majority of the county is white, but we do have a number of black Republicans who are quite active."

Gary Alexander, chairman of the county's Democratic central committee, said his group also takes no position on individual candidates. Alexander also said that the promise of Republican money for candidates is not enough to win them over.

"To me, there is much more involved. There are fundemental differences in principles between what the parties stand for," he said. "I can't see the people of Prince George's doing anything but supporting the Democratic party."

Nevertheless, Smith said there is a "strong possibility" that he will switch his party affiliation. He added that he is looking for more than just assurances of financial backing.

Radamase Cabrera, Smith's campagin strategist, was more direct.

"Even if they opened up the suitcase today, we wouldn't take the money just yet. If we are going to become Republicans, we want to have the rights and responsibilities of any Republican, black or white, including the access to influence the Republican ideology," Cabrera said.

State Sen. Tommie Broadwater, a veteran of the Prince George's Democratic organization and the only black among the county's eight state senators, scoffed at the idea that black faces backed by Republican money could defeat Democratic incumbents.

Voter registration is a concern for Levey in a county where registered Democrats outnumber Republicans three to one. Though many blacks in the county are registered Democrats, Levey said there is room for Republican gains among that population.

Besides Smith, a number of black Republicans with an interest in running for office in 1982 have emerged. They include Prince George's County Executive Lawrence J. Hogan staffer Wilbert Wilson, expected to run for state Senate or county council; former NAACP president Sylvester Vaughns; Joseph Parker, a schoolteacher who ran an unexpectedly close race against Broadwater for the 25th District Senate seat in 1978; and James Whitehead Jr., a 24-year-old staff assistant to U.S. Rep. Jack Kemp (R-N.Y.).

Although Levey does not expect black Republican candidates to support Reagan's policies when Prince George's federal workers face a serious threat of layoffs, he said this remains the year for Republicans to make a serious bid for black support.

"Until two years ago, the Republicans at the state party level just hoped blacks wouldn't vote," he said. "That's not a good idea anymore."