The radicalism of the Radical Republicans was more political than it was economic. The Radical Republicans' economic plan was really not particularly radical.
Some of these men were willing to propose radical plans. Thaddeus Stevens, for example, proposed land redistribution in the South. He proposed that the largest estates in the South should be broken up and distributed to poor whites, freed slaves, and even to Northern land buyers. This would truly have been radical.
As it was, however, the Radicals did not do anything very radical in economic terms. They did not even give any land (not even the proverbial 40 acres and a mule) to the freed slaves. The Radicals did do radical things in politics, but they did not do anything particularly radical in economics.