When I did mine,I used parts from another truck I have.
The cut-outs on the firewall,I carefully laid it out then cut out less than needed so I could roll the edges inward like original.Same when I filled the larger hole,then re-cut it.
Your pic doesn't show all the holes to be filled and re-drilled.
I did use 2 battery boxes to make one that has the correct clamp for the lines.
It's not very hard to do,just time consuming.
Mike.
