Well.... I've bitten the proverbial bullet and changed the TB (very hard on dentures).
. With only 35,000 original miles the 1985 Z had timing belt #2 installed. The first one was changed in 1994 when the car had 29,000 miles and now, 23 years later, and 6,000 additional miles I thought it was a wise decision to change the TB again along with the cam seals and drive belts. Things went well with no dents, scratches or breakage of any body or engine parts. 
Yeah!!!The 20 mile ride (shake down cruise) was, as always, fun fun fun. The next day I decided to prep the car for the chilly days ahead by topping off the gas tank and adding some Stabil. While backing the car into the garage I thought I heard a whining sound from the engine bay. I popped the hood but everything was nice and quiet until I throttled up to 1,300rpm. It sounds like a turbo whine (I don't have one of those), or an over tightened belt causing the alternator bearings to whir/complain (belt deflection of drive belts meet mfg. specs perfectly).
The sound increased up to 1,800rpm, before it was no longer audible. My well qualified, Z loving, meticulous mechanic assures me that the TB tensioner specs are also spot on. He (and I tend to agree) thinks that it might just be all the new belts having to be given appropriate time to properly seat themselves. The whirring sound isn't heard above 1,800rpm or below 1,300rpm.
We decided the I should put on about 40-60 more miles on Z car to see if the sound stays the same, goes away or gets worse. If need be he said he'd back off the tensioner (below specs) if the noise doesn't go away. (F.Y.I.- He said that the old TB slid right off the sprockets without having to touch the belt tensioner). Yikes! Scary, too. 
Will definitely do what has to be done. Just another excuse to run through all them gears. 
Has anyone else had this issue before? If so, was it resolved? Is this "normal" when the belts are changed? And "No." - Frank, I won't let you take it off my hands. Lol.
