The insurance industry has targeted more than 40 domestic and foreign car models for higher policy rates to offset what the insurers say are above-average repair and theft losses for those models.

One major company, Geico, is refusing to insure 29 models that it regards as excessive risks.

At the some time, however, the insurers are giving discounts on policies for more than 30 car models that companies say have below-average losses.

Among auto models selected for higher policy rates are the Ford Pinto and Mustang, Toyota Celica, Buick Skyhawk, Audi, BMW and Datsun 210, 200SX and 280ZX. Autos that Geico refuses to insure include the Chevrolet Corvette, Camaro Z-28, Trans Am, Jaguar and the new De Lorean when it becomes available.

Autos eligible for discounts include Buick LeSabre, Chevrolet Impala, Pontiac LeMans, Toyota Cressida and Volkswagen Dasher.

"We did it (imposes surcharges) because, after we had data collected, (we found) some cars cost more to insure than others, even though they cost the same when they are new," said Elton Stephenson, assistant vice president of pricing for Allstate Insurance Co. Stephenson said that fixing the lowest price to the lowest risk model is more equitable for policyholders and ultimately can enable a company to be more competitive, to write more policies and to make more profit.

Allstate initiated the practice five years ago with a limited number of cars. Since then the company has expanded its program and in the last six months other major companies have begun similar programs.

Actual surcharges and discounts vary, depending on the company, the model and age of the car, the jurisdiction in which the driver lives and the car's particular history of policyholder claims for repair and theft losses.

The increase could be as much as 46 percent for an adult Allstate policyholder who has a clean driving record, a home address in the District of Columbia and a new Chevrolet Corvette.Instead of paying $171 for a semi-annual premium for full comprehensive and $100 deductible collision coverage, the driver would pay $250 -- or a $79 surcharge.

In contrast, Allstate would give a discount of 43 percent to the District adult resident with a clean driving record and a new Buick Century. His semi-annual policy for full comprehensive and $100 deductible collision coverage would drop to $72 from the standard $127 -- a discount of $55.

Collision insurance pays for damage to the policyholder's car when it has been in a collision with another car or object. Comprehensive insurance pays for damage to the policyholder's car from fire, wind, hail, theft or vandalism. f

Here is a summary of the rating programs for the largest companines in the Washington area:

State Farm, the nation's largest auto insurer, places surcharges on 23 models and discounts 23 others from the 1980 and 1981 model years. The average surcharge adds 15 percent to the cost of collision and comprehensive insurance; the average discount reduces the price for that coverage by about 15 percent.

Allstate, second largest auto insurer after State Farm, charges extra for 42 car models and discounts 33 others from the 1974 model year to the present for comprehensive and collision coverage. Premiums are 35 to 65 percent higher on six models -- BMW, Camara Z-28, Corvette, Pontiac Trans Am, Porsche and Triumph -- and 10 to 30 percent higher on another 36 models. Discounts average 35 to 45 percent on two cars -- Chevrolet Impala and Buick Century -- and 10 to 30 percent on 31 other models.

Geico, the largest auto insurer in the Washington area, charges extra for 37 car models and discounts 68 others from the 1974 model year to the present. The largest surcharges -- 18 to 30 percent -- apply to a group of cars that includes the Datsun 200SX, Toyota Celica and Subaru SL. The smaller surcharge of 12 to 15 percent is imposed on a second group of cars including the AMC Eagle, Ford Mustang and Dodge Challenger. Geico also splits cars into two groups when it offers a discount. The four-door Buick Skylark sport model and the four-door Chevrolet Citation hatchback are in the group that qualifies for the largest discount of 30 to 50 percent. That compares to a discount of 18 to 26 percent for the two-door Citation hatchback and Buick Skylark coupe.

Nationwide Insurance charges extra for 29 models and discounts 36 others from the 1981 model year for collision coverage. The company is reviewing statistics now to decide on surcharges and discounts for comprehensive. The collision insurance surcharges range from 7 to 30 percent on such cars as Datsun 280ZX and Mercury Capri. Discounts of 7 to 25 percent on collision coverage apply to such cars as the Buick Skylark, Cadillac Eldorado and Olds Cutlass.

Aetna places surcharges on 12 models such as the Monza two-door and Buick Riviera and discounts 14 models such as Cadillac Deville and Olds Omega from the 1981 model year. In addition, the company charges extra for 9 models and gives discounts for 9 models from the 1980 auto line. The surcharge ranges from 18 to 30 percent; discounts from 10 to 18 percent.

Together, those five companies write more than half of the collision and comprehensive policies sold in the Washington area.

In the past, the insurers generally based rates for comprehensive and collision coverage on the price of the car, its present age, the use of the car and the age, sex and home address of the driver. Then, five years ago, Allstate introduced another factor -- the excessive losses that the company had experiences on particular car models.

For its program, Allstate first calculates the average loss for all of the cars it insured during the past year. That average loss is derived by comparing the dollars paid out for vbehicle damage, repair and theft claims to the dollars taken in for premiums. Then the company checks the average loss against each model's loss and sets an additional charge according to the findings.

Allstate gives a discount, however, when the loss ratio for a particular model is below average.

Newcomers to the surcharge-discount program include Nationwide, which began its plan on Feb. 20, and State Farm, which introduced its version in Maryland in Jan. 1. The system took effect last November for State Farm policyholders in Virginia and the District of Columbia.

Because the insurance program has the potential to change car-buying habits, auto manufacturers are watching with more than casual interest.

Officials at General Motors generally endorse the concept of pegging insurance rates to car repair costs, but they say that the present system hasn't yet been refined enough to achieve just that.

Ted Parker, GM director of service research, said that the insurers are factoring in losses for more than just auto repairs. Losses for cars destroyed in wrecks and for cars that are stolen also are included, Parker said. Since those losses are tied directly to the market value of the car, the popular models with the higher resale value would run up insurance company claim losses more than less popular models, he said.

One example of this would be the Chevette and the Fiesta, which sell new for essentially the same price, Parker said. But because the Chevette is more popular, it could have a resale value of $4,300 after two years compared to $3,500 for the less popular Fiesta, he said.

"We need a system that looks at car design alone," Parker said. ". . .If the rating system is doing its job, it should reward good design features and penalize poor design, and we are for that.

"But if the (insurance) rating system embraces a number of factors (repairs, resale value, theft losses and so forth), it could provide a negative." Companies List Their Exceptions

As examples of industry practices, here are the auto models for which Allstate charges extra or offers discounts on comprehensive and collision insurance and the models that Geico won't insure: Allstate

Surcharges of 35 to 65 percent: BMW, Chevrolet Camaro Z-28, Chevrolet Corvette, Pontiac Trans Am, Porsche and Triumph.

Surcharges of 10 to 30 percent: Romeo, Audi, Avanti, Buick Skyhawk, Cadillac Eldorado, Chevrolet Camaro, Datsu;n 310, 810, 200SX and 280ZX, Dodge Colt and Challenger, Fiat, Ford Pinto and Mustang, Jaguar, Lancia, Lincoln, Lotus, Mazda, Mercury Capri, MG, Olds Starfire, Opel, Plymouth Champ, Arrow and Sapporo, Pontiac Firebird, Renault, Saab, Subaru, Toyota Celica, Celica Supra and Corrolla (excludes the Tercel) and the Volkswagen Scirocco.

Discounts of 35 to 45 percent: Chevrolet Impala and Buick Century.

Discounts of 10 to 30 percent: AMC Concord and Eagale, Buick Skylark and LeSabre, Chevrolet Caprice, Citation, Malibu, Nova, Nova Custom, Chrysler Newport, LaBaron, Cordoba, Dodge Aspen, St. Regis, Mirada Diplomat, Ford Escort, Mercury Lynx, Ford LTD, Mercury Marquis, Olds Omega, Delta 88 and Custom Cruiser, Plymouth Volare and Gran Fury, Pontiac Bonneville, Grand Safari, Catalina and Phoenix, Toyota Cressida and Volkswagen Dasher. Geico

Cars that Geico won't insure: AMC Cobra, Amphicar, Aston Martin, Chevrolet Corvette, Chevrolet Camaro Z-28, DeTomaso, Excalibur, Fairthorpe, Ferrari, Giannini, Ginetta, Jaguar (12 cylinder models), Jeep C-15, Jensen Interceptor, Lamborghini, Lotus;, Maserati, Mazda 360, Mini, Monteverdi, Pontiac Trans Am, Porsche Turbo, 928 and 911, Shelby Mustang, Stulz and TVR 3000 & Taimar.

Geico also doesn't insure three wheel vehicles or "kit" cars such as Bradley GT, Gazelle and Kelmark. And the company has already decided against insuring the new De Lorean car, which is scheduled to be on the market soon.