You can, but you'll get a lot of blocking. Reduce to 720p or 30fps to reduce the blocking.
In order to get rid of blocking in a 1080p at 60fps video, you're going to need increase the x264 CPU preset. The default is "veryfast", but you will need "fast" or "medium" in order to reduce the blocking enough where it would be worth doing the 1080p.
Unfortunately, in order to reach that desired "medium" preset, you need an EXTREMELY powerful computer. Something in the i7-49xx series.