If you're talking about cutting a 2x4 into a pair of 1x4's that are still 4" thick, it's not too bad if you make a jig and use an electric carving knife. It won't cut as cleanly as 703 or 705 but it's very doable.
If you're talking about slitting it to be 2'x4'x2" thick, don't even think about it - it will be a mess and you'll be doing some serious cursing. Buy 2" thick to start with.
Bryan
