340 -727 -3000 stall- Vibration under load - Trying to find source

I assume this has been a issue the whole time you've owned the car?

Some of us are more sensitive to feel, noise, smell, etc. Trying to diagnose over the net can be a real challenge. Meaning it's difficult to tell how severe or not a certain symptom is.

I don't know if you have someone close, maybe even a member, that could come by and give you a second opinion before you start tearing things apart or spending $$$ that might not be necessary.

Crazy as it sounds, I once worked on a brand C for a guy and noticed a very similar feel to what your describing. The engine had a very mild hydraulic cam and when i went to install new VC gaskets i noticed it had polylocs for adjusters. So while i was in there i did a quick running valve adjustment and found the preload was multiple turns down, so i set them like i liked them with a fairly light preload. Gaskets on and buttoned up and out for a test drive and didn't feel that weirdness anymore.

Good luck finding your issue, i'll keep checking in. :thumbsup: