OK I went digging. Per Dave MCcLellan's "Corvette fron the Inside" page 195:
"V-6S AND TWIN TURBOS
To his credit, Lloyd kept the pressure on the engine guys. Their first
response was a turbocharged 90-degree V-6 for the Corvette. They reasoned
that the smaller displacement was needed, both for fuel economy and to
accommodate the turbochargers and auxiliary plumbing. But we rejected
the V-6 engine, and so did the car. The engine caused problems in the driveline
and rear suspension and made the car buzz and the mirrors shake. This
unbalanced V-6 engine configuration was totally unacceptable when
mounted in the Corvette, which had never been designed for such an
engine. So, the engine guys finally got the V-6 out of their system, and we
settled down to work with them to package a twin turbo V-8."
If that is the engine that is a very rare piece of Corvette history. Thanks for posting it.