Sounds like you may have picked up a junk yard special. Back in the days
before the yards tied their prices to new part prices, parts were quite
cheap. Many yards found that they could get more money out of combining
the parts off several cars & selling complete cars. So it was not
uncommon to walk into a yard and see a listing for cheapish runner cars.
Those cars could have a chassis from one car, engine from another, body
from a number of cars.
These days they get so much money from parts, they take appart runners to
sell parts ... or sell them to someone going overseas.