As noted above, Nike's original Vengeance was marketed as a trainer, not a racing shoe. I think these came out in 1985 because I ran in them as a college senior which was fall 1986 and they weren't brand new when I got a pair. They were around for a couple years at least because I bought 1 more pair after college. If I had to guess the weight based on other shoes I wore back then I'd bet they were 10-10.5oz (size 8), so not "super lightweight" but a lot lighter than most. They did have a full air unit in the midsole, but I think Nike had other lightweight shoes back then with a full air unti (Mariah?). One thing about these was they had a severely curved profile. The sole under your arch couldn't have been more than 2" wide.
The poster above is spot on regarding the smell. I always thought it was just me because I usually didn't use socks and I didn't bother to dry them out before tomorrow's run.
I loved the feel of these shoes. Ran my first marathon in a pair. I'd put them in my all-time top 5.