speaking of wristpin bearings, i was wondering same thing,, i heard they were having trouble with earlier wristpin bearings falling apart,,, i have a 09/09/2015 gt5 38mm stroke engine,,,i have looked at wristpins and it seems like there are three types,,, here are pictures of two,, the one is what came in my engine,, the other style is sold by JNM motors,,, should i change to different style,,, the third type has smaller length needles and more solid cage material,,,, and what size drill bit do you use to drill out wrist pin for less vibration ???