Back in the 70's & early 80's at the height of "planned obsolescence" Chevy V8's had a very undersized pot metal cam gear core with a thick nylon coating to bring the teeth up to chain link size. This was done ostensibly for a "silent" timing chain, and they wore out fairly early by todays standards.
I changed out my fair share of these. Once I knew it had to be close, tore the engine down and every trace of nylon was gone and the "core" teeth were nubs, and literally lifted the chain off the cam gear to remove it.
Even with that much slop, these engines ran pretty good right up until the chain jumped around the gear.
Vastly different engine from yours, but my guess is your symptoms are more than chain stretch could produce. Maybe your timing gear marks weren't aligned on the #1 compression stroke?