There are two considerations to ponder here:
1) The color spectrum of the chosen LED as well as its brightness.
2) Even illumination over the entire area of the projected image.
If you're still printing on graded papers, they are only sensitive to blue light. If you'll be using VC papers, they are sensitive to both blue and green. I've just completed a modification of my 5x7 Omega enlarger lamphouse, using an array of cool white LEDs, and I found that the spectrum they emitted was sufficient for VC and was uniformly distributed over the image area, but the warm color of the diffusion material did not allow a contrast above about grade 3. I found a diffusion material that solved that problem and can now achieve grade 5. If you'll be using Ilford VC papers, they recommend use of their under-the-lens filters with a bulb approximating incandescent color (~2800K). But you should have enough lamp output to keep your print exposures around 20-30 seconds; that should help avoid reciprocity of the paper.