Boston — The job gains made by blacks after passage of the Civil Rights Act in 1964 did not fade away in the economic troubles of the 1970s.
That's the conclusion of a study by Richard B. Freeman, a Harvard University professor of economics. Looking at the earnings and occupational attainments of blacks in comparison with whites, Freeman finds that the advances that were so noticeable in the last half of the 1960s were ''neither transitory nor illusory.''
Here's some more detailed conclusions, some of which may be surprising:
* In 1964, black male college graduates had only 41 percent as large a chance as whites of ending up in management. Many such graduates became teachers. By 1979, their management chances had improved to 75 percent as both private corporations and government bureaucracies opened their management doors to blacks. That progress continued throughout the 1970s and into this decade.
* Black males had only 58 percent as large a chance as whites of becoming skilled craftsmen in 1964. Today the chance is 81 percent. Again that shift continued in the last decade.
''There has been a big improvement . . .,'' said Mr. Freeman in a telephone interview.
* Black women nowadays earn about 1 percent more on average than white women. That is because black women generally work longer hours. Corrected for hours, they earn about 6 percent less than white women. However, Freeman suspects that, if education levels are taken into account, ''there is no notable economic difference.'' Nor do the statistics show much distinction in occupational status for black women, though Professor Freeman is aware of the likelihood that individuals may suffer discrimination.
Like white women, black women earn on average some 40 percent less than men on average. ''Women really take a beating in the market relative to men,'' notes Freeman.
* On average, black university graduates do about as well as white graduates. An engineering graduate, for instance, will be paid the same to start as a white graduate and make about as much salary progress on average.
* Black males with little work experience, aged 14 to 24 years old, start out with the same pay levels as whites of the same age and experience. These tend to be high school dropouts or high school graduates. But the blacks drop back from the wage level of whites as they get older. Freeman speculates that these youths benefit from the minimum wage or other starting-level wages when they first go to work. But these youths do not advance as fast as whites at first.
Between ages 25 to 29, however, the relative wage gap between black and white males remains about the same. And for those aged 30 to 34, the blacks catch up a little relative to whites.
Overall, black males get about 80 to 85 percent of the wages of whites. That compares with 55 to 60 percent before 1964.
Mr. Freeman's statistics take him through the 1980 recession, and some go into 1981. And he concludes: ''There has been no slipping on average.''
Of course, Freeman recognizes that blacks still have problems in the labor market. Black family income, for instance, has not risen relative to white family income. It was 64 percent in 1968 and in 1978. But this is because the proportion of homes with male heads of households declined more rapidly for blacks than whites in that period. Divorce and separation, with the financial ills they produce, have been an even greater problem for blacks than whites.
Moreover, young blacks have experienced an employment crisis. Among black teenagers, unemployment reached something like 48 percent in April. Unemployment among blacks as a whole reached 18.4 percent that month, the highest since the Labor Department began recording this statistic a decade ago. The overall unemployment level was 9.4 percent.
The percentage of working-age black males employed, which was 73 percent in 1964 and 1969, slipped to 64 percent in 1979. The comparable figures for white males were 78 percent, 78 percent, and 75 percent.
To sum up, blacks have made considerable progress in the job area. Wage and occupational discrimination has eased. But getting a job, at least for those blacks at a lower-education level, remains a severe challenge.