That is no longer a limitation as of the 1.3.2 release. I quote:
URLFetch API - We’ve expanded the number of ports you can access with the URLFetch API. You can now access ports 80-90, 440-450, and 1024-65535.
URLFetch API - We’ve expanded the number of ports you can access with the URLFetch API. You can now access ports 80-90, 440-450, and 1024-65535.