Super Stock Springs Update

[Dave64 <lt7dave@xxxxxxxxx>]

After chasing after the correct brake setup, I have my '64 Belvedere all buttoned up and back on 4 wheels.  Here's a rundown of what I did.
I installed a later model 8 3/4 rearend (I think it's a '68 B body).  I used my old 741 third member, put new green bearings on the "new" axles, and put new brakes on it (11'x2").  I also installed 3400lb SS springs with the 2" extended front hanger brackets along with new (longer) Mopar drag shocks.  

The result:  I really like how it looks now, but it has a bad vibration starting at around just 20 mph.  A few assessments I make are:  the third member is my old one - I had no problems before, so I'm figuring that is ok.  The axles look fine - don't appear to be bent or anything, so for now I think they're ok.  No change in tires or wheels, so that shouldn't be it.  

This leaves me with the theory that it's driveshaft related.  Either the length of the driveshaft could be an issue (as suggested previously here), or maybe the pinion angle now isn't correct.  Because I changed several things all at once, I've left myself in a position of having several possible areas that could be the problem.  And I also didn't have the forethought of measuring the driveshaft length or checking the pinion angle on my previously non-vibrating setup, so determining if those things are at issue will be more of a challenge.  I'm bummed out that I did a lot of work and now have a car that's essentially not driveable until I get this figured out and fixed.  As always, your help is much appreciated.  What do you guys think?

Thanks,

Dave
'64 Belvedere 2D HT, Auto


      


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