OK mopardad, I got ya. Outriggers. If that's the way to do it then there's no good reason to use 2x2 then. So that's out.

I like the article at http://www.bigblockdart.com/connectors/connectors.htm and it is helpful, but other than overlapping it they don't explain exactly how the 3" wide connector is fit to the roughly 2" wide rear frame rail. What did they do, heat with a torch and pound on it? Smash it with C clamps or a vise? Just weld the heck out of it? Add more pieces to narrow that part? It doesn't say.

From what little I understand about such things, it looks to me like if it were facing the other way (2" horizontal, 3" vertical) the sectioned back end of the connector will fit better over the frame rail, but will be somewhat less convienient to install.

I don't know anything about this stuff, and never claimed anyone has to run them through the floor, I am saying that I don't mind doing it IF it gives a worthwhile improvement in strength.

Looks like the silent majority is voting for 2x3 through the floor in the back and that's the way I'm leaning towards right now. Is it worth doing that way?