I was looking at Edeldbrock's gear drive instructions. Seems as though there is quite a bit of clearance issues associated with installing a gear drive unit. Given the same guy that installed the gear drive also didn't install the flex plate bolts...
I watched all your videos again, your engine sounds fairly healthy with the exception of the high pitch squeal. I think it's safe to say that the front cover needs to come off and the gear drive needs to go.
Here's the Edelbrock instuctions.
http://www.catalograck.com/imgvd/EDE/7890.pdf
I did the liberty of looking at NAPA for timing gears. $36.39 and up. Single roller, double roller, true roller, shouldn't matter. They'll all get the job done.
https://www.napacanada.com/en/search...=nol-veh-conds
While your at it, here's some new Camshafts. The Torker cam is a little much for a street engine, unless you plan on going to the drag strip and doing a shot of nitrous. I've used the Edelbrock Performer before. It's good on the street, torquey down low, but still good power in the 4000+ RPM range.
https://www.napacanada.com/en/search...RefSearch=true
Once you get the gear drive off, you'll be able to tell quite a bit about the engine. Especially if there's a spun bearing, etc...
Hope this helps.
Chris