Driveline vibration --Pinion angle

I have been haveing a ongoing vibration problem that I just can't seem to cure. The car 67 coronet 440 with a 383 and a 727. Iluanch at a idle around 1k shift to 2nd at 5k shift to drive at 5k the rpm's dropand when they get back up to around 5k I get a heck of a vibration for just a short period and it seems that It's coming from the front endof the driveshaft/end of tranny area. I can't give you a MPH as my speedo is way off. I did install s/s springs alittle while back. checked pinion angle today off pinion yoke about 6 nose up.

What should it be nose up or down and about how many degrees?

5-7 degrees down with those springs is what you want.

Is there any way I can do this without cutting and relocating the spring perches? According to Mancini this is what I have to do.

Rear Axle Shims

MOPAR - Rear Axle Shim Package
An incorrect rear axle pinion angle not only robs precious horsepower, but can also cause launch problems and parts failure. Mopar Performance Parts has developed these tapered pinion angle shims so pinion to driveshaft angle can be adjusted to the correct five to seven degrees. Kit includes two each 1, 2, and 3-degree shims.


It`s funny Mancini said that when they sell the shims.

My shims came from Mancini. Welding the perches to the correct angle would be the best possible solution, but lots of us get by with shims.