Check My Measurements...Pinion Angle

[threewood]

Finally got around to checking and hopefully fixing my pinion angle. This is in a 318 poly 4bbl so I am not making any axle twisting power and it is a street car. Installed my super stock springs about 2 weeks ago, and my pinion angle was pointing up. So I ordered some steel shims (4*) and got em installed today. Below are what I measured before and after with all 4 wheels on the ground. Is this good enough for a street car? I have heard 5-7* is ideal but for what and what angle? Both engine and rear end are horizontal to each other.

 

[dvw]

For regular driving you are good to go. If your going to drag race it I'd tip the pinion down another 4-5 degrees. It gets tough to get the rear leaf spring pin to locate a thick shim.
Doug

 

[threewood]

Thanks, it seems to drive smoother too. The 4* shim looks like max without cutting and re locating the perch. There is enough of a nub to locate the springs on the axle with this shim but no more. I may tack weld the shim to the perch just in case.

 

[66chargerpat]

Threewood, may I ask what did you use to get your angles? I changed to a newer tran.s and I have a small vibration. Thanks, Pat

 

[Grabinov911]

My car is so low that the rear diff is actually higher than the transmission - meaning my driveshaft is angled UP. Since my trans leans down, I had to trim my rear diff UP to get the alignment right. I used Allstar aluminum leveling shims between the axle and the perch...

 

[threewood]

Threewood, may I ask what did you use to get your angles? I changed to a newer tran.s and I have a small vibration. Thanks, Pat

Johnson Magnetic Protractor Angle Locator. Bought it off of Amazon for about $14.00. I followed the service manual instructions. Measured driveshaft angle, measured pinion angle (flat pad where pinion snubber mounts, 741 case), and front of harmonic balancer. My rear end was factory so I dont know how it got out of wack.

 

[747mopar]

I had a weird driveshaft vibration, setting the pinion parallel to the tranny is how I corrected it as well. You should be goid to go.

 

[dvw]

I use this , $35 and digital. can be zeroed to any angle , works great
http://www.google.com/shopping/prod...1007649100501800425&q=craftsman+digital+level
I've made lowering blocks trimmed at an angle. Drill a hole for the spring bolt a few thousands tight and install a locating dowel. The dowel is pressed through the block so the spring center bolt fit's in the bottom of the block. Make the dowel stick out far enough at the top so it touches the bottom of the axle tube, that way it can't fall out. Make them any thickness or angle you want.
Doug

 

[747mopar]

Easier yet, just download the clinometer app for your smartphone. I checked it against a level and it's accurate.