Im modifying the factory bracket to install the ECU in the factory location but it seems a little narrow to fit around the Megasquirt ECU. Does anyone have pictures showing what they did to make it work?
Try some pipe strap; Home Depot, Lowes or almost any hardware store will have it.
Some foam sheet or rubber sheet under the pipe strap will help prevent scratching up the outside of the case if that is a concern for you. You can get that at Walmart in the craft department.