^ Dis. Its the length that messes things up. Take a piece of 3/8" drill rod 5' long and whip it around in circles lengthwise and watch it curve like crazy. Do the same thing with a 2' piece and theres practically no deflection. Dia/wall thickness/length/material all go into setting a shafts critical speed.

Although i havent tried one myself I wonder how a CF shaft would work at those lengths? Regardless a phone call to Denny's and Im sure they have an easy bolt in solution. I used to recommend PST but there was some shaky things with later versions of shafts and I "hear" that they are now made in China so..... Hard to always know the right shop to buy from regardless of what your looking for. Its changing all the time

 

i lost two of them in my 2wd ecsb. the 4wd guys have less of a chance of narfing them due to a shorter shaft that is used.

cc and ecsb 2wd guys who say they are smooth over 100 mph. take warning. it WILL happen to you.

 

I say it's still risky even on the 4x4's. At a minimum, I'd have the stocker rebalanced.

 

How much does it cost generally do have a driveshaft rebalanced?

 

to 150mph

 

A two piece shaft seems to be the answer if length is the problem.

 

My truck driveshaft vibratea like crazy at 98 time fo get a new one from driveshaft specialities...