George C. Wallace, 63, seeking an unprecedented fourth term as governor, leads the pack running in Tuesday's primary, but analysts see his once-comfortable margin slipping as some black support erodes and other voters question his age and health.

Elsewhere on the Democratic ballot, "boll weevil" Rep. Richard C. Shelby finds himself in hot water for supporting President Reagan's spending cuts in Alabama's economically depressed 7th Congressional District, where unemployed steelworkers have pushed jobless rates there to 20 percent.

Wallace, half-deaf and confined to a wheelchair since he was shot in an assassination attempt in a Laurel, Md., shopping center during his 1972 presidential campaign, is expected to face either progressive Lt. Gov. George McMillan, 38, or powerful House Speaker Joe McCorquodale, 61, in a runoff on Sept. 28 if he does not win a majority Tuesday.

In Connecticut, Sen. Lowell P. Weicker Jr. (R) and Gov. William A. O'Neill (D) are unopposed in their primaries and their general election opponents have been selected at their party conventions. In Florida, Gov. Bob Graham (D) is expected to win his primary handily and Sen. Lawton Chiles (D) has no primary opposition but faces a tough race in November.

In Arizona, Gov. Bruce Babbitt (D) and Sen. Dennis DeConcini (D) are unopposed for their nominations but Republicans are fighting for the chance to oppose them in November.

Alabama's overall unemployment rate is 14.5 percent (and climbing), second only to Michigan's. Jobs rival personalities as the main issue in a governor's race filled with innuendoes, whispers and dirty tricks.

Wallace offers himself as a populist job savior at rallies. At one that drew some hard-luck steelworkers to a Bessemer shopping center Thursday night, he told supporters that his trips abroad as a former presidential candidate gives him access to "foreign industrialists" who might favor Alabama with factories.

Many believe such boasts, but not enough do to give Wallace a victory without a runoff, political analysts predict. "We've seen a good deal of erosion in his lead in the last few weeks," said Natalie Davis, a political science professor at Birmingham Southern College whose surveys give Wallace 40 percent of the vote, down from earlier polls.

For the first time last week, Davis' polls showed black support for Wallace dropping below 50 percent, as the professed reformed segregationist tries to battle the decline with ads on black radio stations and direct appeals to black ministers who hold sway over much of the state's 25 percent black vote.

McMillan, a courtly, scholarly man portrayed as a liberal, or worse, by Wallace for dismissing the statewritten school prayer as "a joke," counts teachers and Alabama's black caucus in his corner, giving him a slight edge in some polls to meet Wallace in a runoff.

Conservative McCorquodale, a tree farmer, small-town banker and Tennessee Ernie Ford lookalike, counts the most money ($1.2 million raised), drawing businessmen and many longtime Wallace supporters who don't believe the former governor is up to another term.

Such defectors include T. (Hunky) Danelutt, 70, a retired businessman who has backed Wallace in every race since 1958, but now frets about his fitness to govern. "He forgets, you know, he forgets a lot," said Danelutt, passing out McCorquodale brochures Friday in Sylacauga, a former Ku Klux Klan Stronghold outside Birmingham.

Meanwhile, Shelby defends his sizable lead against a black-labor coalition attempt to portray him as a turncoat who has savaged social programs. Anti-Shelby TV ads show blood dripping onto a hospital floor as opponent Jack Kartus, a retired Jewish merchant, says, "Shelby has drained the lifeblood out of the 7th District."

Shelby counterattacks, with his own ads accusing Sen. Edward M. Kennedy, House Speaker Thomas P. (Tip) O'Neill and Kartus of being free-spending liberals.

"I wasn't elected to go up there [to Washington, D.C.] and be a liberal Democrat," Shelby says.

Sparring in the governor's race has sunk to even nastier levels. Elderly women have been cursed by so-called telephone fund-raisers impersonating McCorquodale staffers. Family-style TV ads showing McMillan and wife serve to counter opponents' innuendoes about his degree of macho, says co-campaign manager Mary Brabston.

Wallace has fought rumors of incapacity ever since he stayed off the stump for a few days, suffering from what aides called laryngitis.

Even Republican Emory Folmar, the pistol-packing ex-Marine who rules Montgomery as its "mayoratollah," hasn't escaped the old-fashioned Alabama mud-slinging, even though he is unopposed. The innuendoes circulating about him concern a nonexistent out-of-wedlock child, which staffers treat as a big joke. Folmar will face the Democratic nominee on Nov. 4.