Mapping network drive with specific port

I'm not sure it's that easy to change, if at all. The NetBIOS ports are basically set, and Windows machines are going to expect to contact remote machines on those port numbers. So you'd have to change both the port NetBIOS is broadcasting from and the port that NetBIOS is listening on, meaning you'd have to change it on all machines in your network.

Assuming, again, that it's possible in the first place.

If you're looking for this as a security solution, security through obscurity isn't always a good bet as a good port scanner like NMAP will still find the ports with no trouble at all. I would instead look into a software firewall solution that will drop all NetBIOS requests from outside your network, or even outside a given range of IP addresses.