Yes, they are, but they may be hard to come by. Look at my links page for sites dealing with 8mm filming. Some have more info on where to buy film stock. Alternatively you may consider having them transfered to video. A variable speed projector may prevent lines traveling up or down the screen.
Some video cameras have a 'slow shutter speed' option that eliminates the flicker to a great extent.
As I wrote on my main page, I may have some data on file. You will have to realize, though, that I can only give a few details such as the date of manufacture. Remember that this is a free service I provide and that my time is limited. So do Savoy Hill Publications, Great Britain. Ask their 'Cinema' list of xeroxes of publications on mostly British movie sound projectors.