That was also my thought Mad... I fixed a 416 done by a local shop that has two pistons in backwards. It seemed fine during the break in, but hit valve and piston when driven hard.
Yes, I have seen it before. The 340 that was in my 70 Dart had all the pistons installed upside down with all the valve notches facing the bottom of the cylinders. With a Mopar 484 Purple cam in it I missed a shift to 2nd without a rev limiter in it. " I just got the car" The valves ended up hitting the pistons at about 7200RPM, it dropped a valve and took out a cylinder/piston/rods/Crank/Block and everything else in its path......, I will never run a car, especially a 4spd without a rev limiter again. This was about 4 years ago. Learned big time on that one.:angry5: