I have found the Slant 6 to be nearly indestructable. A good friend had a Slant 6 'Cuda and had a fresh 440 ready to go in it. We were at an outdoor party and someone bet him that he couldn't blow it up. He put a brick on the gas pedal and that poor motor ran full throttle for at least a half hour and never skipped a beat. Finally, we shut it off because some drunk chick started bitching at us because she couldn't hear the music over the sound of the motor screaming. A Slant 6 might be the ugliest engine ever produced, but they are one dependable SOB.