Need to check if the tdi will bee too tall.
The Detroit/GM 6.2 would be a bolt in.
With a turbo they make decent power.
the non turbo one in my dads 82 Blazer got super mpg.
My brother has a 88 FIero GT with a Caddy 4.9 V-8 in it. Love to see a Fiero with a tdi/5speed.
Probly get 60+ mpg.
I saw a Readers Ride in Hot Rod I think it was a few years back of a 77 Vette with a GM 350 diesel. Owner claimed it was good for 38mpg.
I think the TDI would be better suited for the Vette because of the lightweight aluminum construction. I don't know anything about the GM diesels, but if you can run aluminum parts, heads, waterpump, intake, etc like the common SBC, then that would be great. I don't know how sporty it would be without a turbo though.
I have a 71 Camaro, 57 Chevy, and 56 Ford truck, and I'd like to see any of them with a TDI or comparative diesel for killer mpg... and dagger-stares at the car shows.