Sorry I got carried away on the project & by the time I remembered to take pictures I had the outlet tube firewall sheet metal done.
This is the firewall before...
and with the intercooler tubes part of the sheet metal in place.
The inlet side is just a simple pie plate deal that will be trimmed & welded into the firewall eventually.
The outlet side was a little more complicated. I didn't want to run the plumbing off to the side (the way it's usually done). I wanted the carb hat facing straight back. Also, the engine is set back about 4" from the stock location. So, the 4" inlet tube has about 3/8" clearance between the windshield and about 1" clearance for the distributor. It's all pretty close but it fits. . The "through the firewall sheet metal'' for the inlet tube ended up looking sorta like shoving the flange through a hefty hefty trash bag.
...and here's what it looks like from "the office".

15th Annual DRAGLIST Nationals Sometime in 2020. Somewhere in the USA.