Throwing in the towel on my 68 Barracuda project.

I can only admire your ability to make a decision. I wouldn't attempt to sway you one way or the other. Me... I offer to sell my 67 vert project in one week, then turn around and spend a couple more hun' on it the next week.
As for the bypass surgery, My dad got a 5 way bypass. I forget how many years ago, at least 20. Today we've all lost count of how many stints have been installed, 9? 11? Anyway... He hit 75 yrs old last December. Although I don't know how old you are, I have to think it's far from over or hopeless mate. Best wishes to you going forward.