I am ready to bolt down the aluminum plates for the engine motor mounts and would like to use Bronze flat head 3/8 machine bolts as I have a good supply of these and SS 3/8 FH is not available in the area. I am using your idea of flat heads countersunk as I relocated the rear motor mounts on the Universal to fit the small pan better and dont want the bolt heads to interfere with the engine placement. Is there a strength or corrosion issue with Bronze?