Pinion angle retard!

Slow85SS

Daily Driver
Feb 3, 2013
14
0
0
Layton, UT
I'm trying to figure out what angle to set the pinion yoke to.

I have a 85 Monte with an LS6/4L80E with BRP engine mounts, G-Force TH400 crossmember, UMI non adjustable LCA with UMI Adjustable UCA, and a QP 9" rearend. The control arms are polly bushings and the QP rear has rubber bushings. The car is not a DD but still see's more street time then track time. It only pulls a 12.9 at 4200' elevation.

It seems the more I read about setting the rear pinion angle, the more confused I get. Some are saying the rear pinion needs to be pointed down, some say I need to point it up, some say I need -1 or -2 or -3 degrees and ignore the transmission measurement... I think I'm just over complicating this in my head and worried about throwing a driveshaft.

When I take my measurements at the transmission output I have a 1 degree rear lower then the front. I measured my drive shaft and have a 1.8 degree rear lower then the front. Which way should my 9" rear yoke point and at what degree?

Can someone please help the pinion angle retard! curse_sign.gif
 

TNTS79

Dragway Regular
Jan 6, 2006
1,252
0
0
Illiniois
-2 pinion angle. As you apply a load to the car the rearend will try to rotate forcing the pinion yoke towards the floor pan. Depending on your bushings solid / poly you can get by with running more or less pinion angle by changing control arm lengths. Longer uppers result in less - or possibly + pinion angle. Shorter uppers will result in greater - pinion angle. Or the opposite is true if you change the length of the lower control arms. Check out baseline suspensions.com
 

Doober

Moderator
Jun 2, 2003
14,704
1
38
Catalina, AZ
www.cardomain.com
I've usually figured on the angles between the tailshaft and pinion lining up, and shoot for a slightly downward angle on the pinion from 0.
 

woody31

Frequent Racer
a good baseline for my elky is -3*,,the more you increase your working angle tho more chance there is for vibration,,check and make sure..really sure the engine and trans are true and level,,not close,,,level,,,or it will never be right,,wheel hop,,spinning ,,,ask me how i know,,,good luck,,, cheers,,,,
 

81rustabu

Dragway Regular
Apr 16, 2011
859
0
0
pinckney,MI
I have stock control arms on my car is it possible to adjust my pinion angle? If so how?
 

SSedan64

Dragway Regular
Oct 5, 2009
948
0
0
MACON, GA.
With stock CA's the only way you could would be to weld up or weld a plate over the existing mounting holes and redrill the holes in a different position.
 

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