Never heard of Blue Devil Head Gasket Repair before. I'd hesitate to try anything long term, but it might be worth it if you're in a bind. I'm honestly shocked it lasted 50k miles, that's pretty darned impressive.
Something I need to share about my own Headgasket issue. I kept driving it because "I needed it" and the leak was very minimal and only decided to tear it down because it started to get "slightly" worse.
What I found yesterday after further inspection is that the occasional action of the piston coming up against even the slightest amount of coolant in the Cylinder ate up the Piston Skirt, the Rod Bearing and warped/cracked the Head.
Now I am looking at having to replace all the Pistons(for matched balance reasons), Bearings and the Head. It is not just a Headgasket issue any longer. I will need to mic the Crank and hope it has not also been hammered flat on that Journal. If I had tore it down when it first reared it's head as a problem I could have gotten away with just a New Gasket.
Now I will also be driving a different vehicle for ten times longer while I fix all the additional residuals.
Just food for thought.
