Someone made a conversion for it, I don't have it saved though, if search for it you could probably find it.
I used this spreadsheet though, which someone else made that predicts your MCAT score based on your FL percent correct. The person that made it used data from I think 40-50 people who took both the FL and then the MCAT.
Just enter in your scores as decimals and it'll give you a range you're "likely" and "definitely" going to fall in.
EDIT: This thing isn't completely accurate by any means, but it helps give you a little idea where you might be at.