Quit worrying about it, lol. Roll with the punches.
If it were me I would hang the headers from the inner fender with some wire, undo the cross link and slide it through the header and leave it unhooked on the driver side. Drop the engine in and get it lined up and loosely bolted. Once it's somewhat lined up check for fitment and any possible interference, adjust accordingly. I know when I put my headers in I had to ding the tube next to the steering column coupler as it was hitting, but that was it.. Don't forget sealant on the end bolts/studs on both sides as they are "wet" holes.
I would also buy some heat wrap and wrap the starter, especially if you are running a OEM starter to avoid heat soak, and I also put a piece of silicone high pressure hose over my starter wire to keep it protected from the heat.
Lastly keep track of the new words you create while installing them................
