Originally Posted by 2gntTalon

they are needed. I have had 2 disks fail on me due to vibrations from lack of dowel pins. I had to take my bellhousing off my tranny and use a dial indicator to find out if mine was off alignment... I then realized I was missing a dowel pin and replaced it. I haven't had a problem since. I previously called southbend clutch and he recommended i do this. I also talked this over with bay city and they agreed with me. Sprung disks will fall apart from the vibrations of the clutch disk and the flywheel not spinning within sync.
this is my clutch disk after running it for 7500 miles with no dowel pins-