Anyway he said he cut the hole on the back at 4.75", I ran the numbers and that seems like its going to be abit too high of a tuning.

Furthermore he said he would rather have an actual port, or something with a lip on it to cover up a less than perfect hole cut.
Something from PE would do.

Given where he is at right right now with volume , please recommend a port from Parts Express as well as a good safe lenght to go with.
Personally id rather have a too long of port then too short.

I'll make him take pics of them when he is done...this is his first speaker project but he is an excellent automobile restorer so already know these are going to come out sweet looking. He has opted to finish them with Formica laminate.

Thanks , and I am sure he will appreciate it as well.

One way to give an attractive smooth look to the port is to laminate it with a thin plastic strip. Sign makers have just the stuff. Formica might work too. Another thing I personally like to do is to paint the edge.