I recently bought the following suspension components for my 69 chevelle to improve hook / 60 ft times at the track:
- Jegs adjustable upper rear control arms
- Jegs adjustable lower rear (like Southside Machine Lift bars)
- Competition Engineering adjustable drag shocks for all 4 corners

I didn't install anything yet and was reading the instructions on the lower arms and it's talking about setting pinion angle with the lowers. I thought I was going to be using the upper arms to set pinion angle. Should I be using these types of upper and lower control arms together? Did I buy the wrong stuff? I'm feeling kind of dumb right now.

The adjustability of the lowers is achieved by the rotation of the bracket that goes between the axle housing brackets and the arms themselves. When the desired angle is reached, you're supposed to anchor the intermediate piece to the rearend.

I have Lakewood lift bars on my '66. I found that at full extension (longest possible position), they still seem to have moved the rearend a little forward. This in affect, rotated the pinion upward further than the stock arms would have. My previous stock adjustable uppers (eccentric varies the position using the bolt for the bushing attached to the rearend itself) did not provide enough adjustment to really obtain optimal angle.

I now have edelbrock adjustable uppers. When these were enlisted to correct the angle, I discovered that the rearend was considerably forward of the stock location. This was very evident when installing the driveshaft. My plan now is to remove some metal off of the intermediate bracket, where it is in contact with the axle tube, therefore allowing the axle to locate further towards the rear of the car.

The recommended means of securing these brackets is by drillins and bolting them to the original axle mounting bracket. In my case, I chose to tack weld it into position.

Pay more attension to determining that the rearend is positioned square, rather than relying on symetrical APPEARING bracket posiition. One way would be using a tape measure, comparing left and right wheel base distance.

Good Luck

thanks for the info, rowdy. especially in regards to squaring up the geometry. i wish i had bought the edelbrock arms. the jegster upper arms use no bushings at all -- just metal on metal with spacers in rear and spherical rod ends on front. i bet they're going to be noisy as hell on the street.

i'm kind of wondering if i even need the lower lift bars. i could just use the adjustable uppers to set pinion angle and re - use my stock lowers (they are boxed and have fresh urethane bushings). if you see this post again, let me know what you think about that.

thanks

I agree that you are probably better with a urethane bushing on the street. There is however a difference between setting pinion angle and setting the intersection point. The lower lift bars will change the imaginary point of intersection of the 4 link suspension moving the point back closer to the rear giving you a better hit at the rear tire. Also there is a difference between setting just the angle of the pinion and total pinion angle. You are not just setting it in relation to the ground, you are setting it in relation to driveshaft angle.