I've been making enlarged negatives all afternoon. I got some ortho litho film from Freestyle (cheaper than lith film in the UK unfortunately otherwise I'd buy it here) which you just use like you would paper under the enlarger. Develop by inspection in trays in ilford multigrade 1+9 dilution which takes about 40-50seconds. It's not that hard, I wish people would stop poopooing it and just shove themselves off to the d-route of doing it. From what I can tell, lith film can be more economical than ohp film too.
I didn't reply to this sooner because the OP seemed to suggest they wanted 8x10 enlarged to 16x20 which is a bit beyond most people's enlargers... but if they mean enlarging to 8x10 size, that's not hard.
I was using 4x5 fomapan100(panchromatic film) before I got the lith film and that's a little more fiddly, working in complete darkness but it does give nice results. I still had to use multigrade paper developer to get a nice high contrast result out of it, though (5 minutes dev time, in case anyone is wanting to repeat my workflow). So give it a try if you have a darkroom, you can get really huge lith film from Freestyle, and if it's not big enough they do 100-400ft rolls in various widths up to 40inches wide if I remember correctly...