Don't have a 69 book, but do have a 71 book. Idle should be at 550 rpm. I would set it for 600.
The whistle could be a # of things.
#1 Vacuum leak (also causes weird fuel mixtures and missing)
#2 Exhaust leak. Had a guy bring a street rod to me. Said the new crate engine had a rod/ main knock and wanted it fixed. Turned out being a exh donut on sanderson headers. Sure sounded bad.
#3 put the air cleaner on. It is calculated into the mess by GM engineers.

By veiwing the vid, here are a few things. Slow down with the taping. I was trying to look at things in detail but you would not stay still long enough. Things like the firing order.
Your vac adv seems to work good. I like to see these inlines get 20-22 degrees adv idling. 8 degrees fixed plus whatever the vac can adds, which is around 15-20. My book says the 250 adds 23 degrees with 16" vac.
Is the timing vacuum port live at idle( sucking) or only when revved up alittle? I bet it needs it. Tom


Inliner Member 1716
65 Chevelle Wagon and 41 Hudson Pickup
Information and parts www.12bolt.com