To add...

These motors do hold up good for what they are, so do the trannies for that matter. There always is a weak link, no matter what motor is mass produced or home built. I do believe some people push these motors a little too far sometimes though, thats my opinion. Also, every motor is different from the other, for example No two L67s will be alike, many things factor in this... Tolerences and even how the motor was initially broke in factors in this situation.