CLASS RACER FORUM - View Single Post

Rick Kagawa · 10-01-2009, 06:20 PM

The closest guess I can post is that you have too small a drive shaft. I drive a 1970 Chevelle with a L78 in stock. I clear the traps at about 7700. I originally had Strange Engineering build me a drive shaft. I always had a vibration at the top end. I could never figure out what it was. I broke a pinion in the burn out and it turned the drive shaft into a pretzel.

I started to look for another drive shaft I looked into Mark Williams drive shaft. I was never really happy with the Strange drive shaft. They sent it to me and it wasn't the length that I had ordered. I had it shortened and the shop had to also rebalance it because it was out of balance from the factory. It was a 3 1/2" in diameter.

When I called Mark Williams they said that the old one was too small. It causing whipping of the drive shaft and stresses the U joints. I got a 4" diameter one. When I ran it for the first time the vibration had disappeared. The diameter of the drive shaft is determined by the length and the RPM at which it will be run.

I hope this helps.

Rick Kagawa

10-01-2009, 06:20 PM	#1
Rick Kagawa Junior Member Join Date: Apr 2008 Posts: 32 Likes: 1 Liked 3 Times in 1 Post	Re: Driveshaft vibration The closest guess I can post is that you have too small a drive shaft. I drive a 1970 Chevelle with a L78 in stock. I clear the traps at about 7700. I originally had Strange Engineering build me a drive shaft. I always had a vibration at the top end. I could never figure out what it was. I broke a pinion in the burn out and it turned the drive shaft into a pretzel. I started to look for another drive shaft I looked into Mark Williams drive shaft. I was never really happy with the Strange drive shaft. They sent it to me and it wasn't the length that I had ordered. I had it shortened and the shop had to also rebalance it because it was out of balance from the factory. It was a 3 1/2" in diameter. When I called Mark Williams they said that the old one was too small. It causing whipping of the drive shaft and stresses the U joints. I got a 4" diameter one. When I ran it for the first time the vibration had disappeared. The diameter of the drive shaft is determined by the length and the RPM at which it will be run. I hope this helps. Rick Kagawa