After holding up the loom, etc, there are a few wires to adjust in length. I think that there will only be a bit of extra length if I mount the ecm low behind the passenger seat. This means that by enlarging the hole in the f/w, I can use the Bonneville grommet and keep that big square connector. In other words, I ain't cutting all the wires.
On a more somber note, I found a hole in my block (or intake) that I can't account for. I'll post a pic later. It's round, so I'll assume it's either an inspection port or a frost plug hole.
Gary