WASHINGTON (AP) _ Lawyers for General Motors Corp. and the government gave a federal judge starkly different final assessments as they recapped the evidence presented in a two-year trial of charges that GM's 1980 X-cars are unsafe.

GM attorney Thomas Gottschalk said in closing arguments Wednesday in U.S. District Court that ''the record overwhelmingly demonstrates that the 1980 X- car braking system is not defective.''

Special assistant U.S. Attorney Lawrence Moloney countered that the government had ''gone far beyond what we need to prove'' to show the cars are dangerous.

The non-jury trial ended when both sides completed closing arguments, but it is expected to be months before Judge Thomas Penfield Jackson issues a decision. The trial started in March 1984 and was in session more than 100 days over the next two years.

The case covers government charges that GM sold 1.1 million 1980 X-cars - including the Chevrolet Citation, Buick Skylark, Oldsmobile Omega and Pontiac Phoenix - when it knew their rear brakes tended to lock too quickly during stops, sometimes causing dangerous skids and spinouts.

The government wants the cars recalled and repaired, and GM fined $4 million. An estimated 700,000 to 800,000 of the vehicles are still on the roads.

Gottschalk told Jackson it was time for the government to ''face the moment of truth'' and explain why it hadn't presented engineering evidence or expert testimony proving the X-car brake balance to be defective.

He said an analysis of accident statistics confirmed GM engineers' expectations that the cars would perform well on the road despite some problems detected during early company tests.

''It shows that the X-car was doing a good job for consumers by keeping them out of accidents,'' Gottschalk said of the statistical analysis. He added it was a sign of confidence in the car that many GM officials and their families drove 1980 X-cars for personal use.

Moloney, however, urged Jackson to give heed to 5,000 consumer complaints about the car, saying they are ''indicative of thousands of performance failures in the field.''

''The engineering data tends to support the consumers,'' he said. ''They're testifying about something real.''