Ballysillan and Springhill argue that the results stem from intensive teaching and parental support rather than from "playing the selection game". But the gains are under threat in one of the schools because it can no longer afford the smaller classes.
At Ballysillan, where 70 per cent of the 170 children are entitled to free meals, 12 pupils in the past three years have gained grade A in the selection tests compared with two in the three years before that. This year, six pupils - twice the previous record -got the top grade.
"We brought in part-time teachers three years ago to help with special needs," explained Adrian Thompson, the principal. "This has given class teachers more time to devote to pupils. We targeted Year 4 classes and that is now working through to Year 7.
"Our more able children have been producing better work because they are getting more teaching. At the same time our special needs register has halved from 101 to 50 and the number of pupils two or more years behind in English or mathematics has fallen from 50 to 10."
Funding of Pounds 80,000 came from Belfast Education and Library Board and the Making Belfast Work initiative, but the programme cost the school Pounds 120,000.
"We will probably have to pack it in now, which is a great pity because there were great benefits for the pupils. We are very concerned about all of this," Mr Thompson said.
At 410-pupil Springhill primary, the tally of A grades rose from five in the 199394 school year to 10 last year and 14 this time round. Grades B and C have doubled from five to 10 over the two years.
Principal Ronnie Lamont put the good results down to parental support and good teaching, with help from the board, Making Belfast Work and the Education Department's Raising School Standards initiative.
"With this support, why wouldn't we be improving and getting people who want the choice to take up places in grammar schools? The pupils have been well taught since Year 1. We are not teaching them tricks, as you can do with intelligence tests. They have had a continuum of good teaching and are able to produce good results."
Parents have their own room in the school and are becoming more involved in their children's education; almost 20 are taking courses offered by the Belfast Institute for Further and Higher Education on reading and arithmetic.
"We are not talking about intelligence here, but parents who want to make sure their children are studying for high targets. Over the past few years we have had more children taking the tests and accepting a fairly strict schedule of work, including extra study over the summer holiday. We only succeed in this school because of the close partnership," Mr Lamont commented.