Ive heard once that the Oldsmobile Jetfire Turbo had a T5, but only seen that written once, ever...

And heres the pics of the turbo setup on one...
http://www.geocities.com/v8mgb/turbo.html



Even if there was a turbo called a T5 in the 60s, itd make even a RS500 T4 look like a modern design, and thats a load of shit today...