I just need some help with some basic designs and just need to know some port lengths. I had a basic program years ago and wish I would have kept it!

This is for a guitar cabinet I'm experimenting with.

I have 2.8 cubic feet internal volume.
I need a tuning of 80hz (like I said, guitar cabinet!)
I have some 2" x 1" ports I would like to use if possible. Barring that, I have some 1.5" ports and of course can get 3" or 4" or whatever if needed.

Or if you know of a free software download that will do this basic stuff that would be even better