Comp cams xe268h for 318

AFAIK factory teener pistons don't have eyebrows.
I had a nice 73ish Duster back in the day with a 318. I bought it cheap, and checked out for a quick flip. I sold that car for about 350, and always with the statement that I would buy it back for 50 no questions asked.
One time it came back, and the guy said it wouldn't start. No biggie I gave him his 50 and he was happy. So I cranked it over and could tell instantly it had no compression........ which I quickly traced to the valves. I pulled a head and it had 4 bent valves. And same on the other side. And the witness marks were on the tops of every piston. No eyebrows. So I smoothed the crowns,No biggie, and slapped a different set of heads on her and put her up for sale again.
Then, I just had to know how a teener could do this, so I contacted the previous owner. The story I got, was him and some buds were at a beer-drinking bush-party and decided it would be cool to see a teener blow up revved right up, with a brick on the gas pedal. Well, as I recall, the PO said that after 20 minutes it was still revving to the moon so one brave soul dared to reach in and turn the key off. ...... and after that, it wouldn't restart.
So my guess is the valves floated, the lifters pumped up and the valves kissed the pistons. And as long as the thing was wound up, it continued to run.
I made some good coin on that car, selling it several times.
I still have the heads; they're the ones in the stack with 4 missing valves.lol.