interesting mild turbo setup

I him saying something along the lines of, its what we had at the time.
Exactly.
When I did mine (1979), there was not much turbo info available. So it was easy and cheap to get a turbo from a salvage yard from a similar sized engine. It took me quite a while to get mine decent. Several different carbs
(Holley 500 2bbl worked the best). Tuning was difficult (no such hing as a wide band EGO, or "electronic boost timing control"). All I had was a EGT from an aeoplane. I did break rings, pistons, and head gaskets, before I got it decent. I am actually rebuilding the engine, with a better cam (turbo grind), and electronic timing control, and a wide band, but the turbo setup will be the same.
Oh, I did have water meth injection, that was just a windshield washer system that turned on at 5psi and sprayed right down the carb. I will be keeping that but using progressive control.
I could drive my 65 V-100 to the track (about 18 mpg) open the exhaust, put on the slicks, and run low to mid 13's at around 104 MPH, at about 11 PSI. That was a 170 with the Corvair (rajay) turbo, 168 CID corvair.
EDIT: At the time I lived in NJ, and had to pass state I&M inspection. It passed emission specs for a 1980 vehicle.