OldskoolRcr

iTrader: (4)

Read all through the search forum, so many different ways to do it, I am more confused now then before I read it all, some say Madmans way of doing it is correct, (put the angle finder on the bottom of the torque arm and thats it), others says find angle of DS at rear, then angle on bottom of rear torque arm plate, . Heres what I got. Bottom of DS at the rear (0). On the torque arm plate on the rear as BMR says to take your reading I have (-3 )pointing doward. So tell me is it -3 Pinion angle? And whats the best angle for a TH400 w/9"nfor drag racing.

vjo90rs8

iTrader: (9)

Yup, -3 is correct. Makes it a lot less confusing since you measured 0* on the driveshaft. Most people get confused with the positives and negatives, once you pick a reference, up is positive, down is negative then everything else is just addition and subtraction.
-3* is definitely on the "extreme" end for a street car and since you have a drag car that is a good starting point. I guess the correct and optimal angle depends on how aggressive your setup is.

02 BLK WS6

iTrader: (11)

I measure at the transmission and at the rear end. Let's say that the transmission measures -3*. If you want a total of -2*, then you want the rear end to measure -4*. If the rear end measures the same as the transmission, then you are at 0* meaning that the driveshaft is in a straight line with the transmission.

If I am wrong, someone go ahead and correct me.

CW00BlackTA

iTrader: (31)

Your goal to minimize drivetrain loss is to have the pinion shaft parallel with the trans shaft at WOT (since you are racing this car). An easy way to do this is to measure at the back of the transmission as 02 BLK WS6 did and then set the pinion flange at the same angle. That puts you at 0 degrees. Then adjust the pinion downward 3 degrees to get your -3 number--which sounds like a good starting point for you. The idea being that there is a 3 degree mismatch until you go WOT and then the pinion comes up close to being parallel to the trans shaft.