@rubydist - Yes the noise definitely changed in response to rpm. If it’s another intake leak, it would have to be one of the two runner-flanges right next to the timing belt cover. I’ll find out in a couple hours when everything is back together.
In the meantime, I’ve redone the timing belt tensioner for the 4th (5th?) time... strictly following the ‘89 sho engine operations book
1. Set crankshaft dampener to theoretical TDC and ensure that cam sprockets line up to their respective timing marks.
2. Loosen tensioner so that only the spring applies force against the timing belt.
3. Rotate crankshaft dampener just shy of two full revolutions and align yellow timing mark on dampener at zero on lower belt cover.
(I’m assuming that this step is for the sole purpose of distributing any slack in the belt)
4. Pop the hatch on the lower timing belt cover and torque the tensioner retaining nut to approximately 25-37 lb/ft.
5. Continue dampener rotation until white timing mark lines up at zero.
That’s the abbreviated procedure for tensioning a belt already installed. If I continue to observe a whine when I fire it up in a few hours, and it doesn’t turn out to be another air leak, I’m not certain if I should attempt to place less tension on the timing belt...