Firewall cutout to accommodate engine placement.
I was pretty nervous about cutting into my Ford, but after checking the measurements over and over again I finally worked up the courage to do it. It was easier to cut than I thought it would be. Between my angle grinder and my reciprocating saw, I knocked it out in about 30 minutes.
With the freshly added cutout, I was able to walk the cab into the position it will be in when mounted. So, the next step was to get the precise measurements of the front cab mount offsets.
Theoretical driver-side front custom cab mount ('59 cab to '84 frame).
This was a little tricky...