Probably 99% or more of that 8 hours is spent waiting on the server. You can't speed it up by fiddling with the client. Of course you could parallelize some fetches - but that is expensive for your good-will information provider.

Probably your best bet would be to package up the already-downloaded text file (compress the heck out of it) and ship that off with your code. Then a bare machine will load that file first before updating from the server.