Driveline angle questions with Speedtech components

[cpd004]

I have a 71 Firebird with Extreme front sub frame. It has an Ls3 and 4L60e.

I recently had some issues with the original 10 bolt and ended up getting one of their 9" axles.

The rear has their torque arm setup.

There is no way at all to measure the bearing cap of the front U joint as Spicer suggests. Best I could do was at the harmonic balancer face as they list in their Mopar instructions I happened to come across.

I am using a Klein digital angle finder. It is a small square device.

At the balancer, I see 2.8 degrees down. There are several shims between the trans and the trans mount. There is no room to go any higher at the tail of the trans if that's what is needed.

The driveshaft actually runs upward at 1.0 degree.

The center section has approximately 4 washers as shim and runs upward at 1.1 degree.

Their instructions at section 4 on page 20 ( https://speedtechperformance.com/wp-...rm-20300-1.pdf ) say this:

Pinion angle should be within range at the ride height as stated above. If you feel a drive shaft vibration at
speed, you may need to adjust your driveline working angle. We have found this to be at optimum on our
ExtReme products between 1.5-2 degrees. Use shims on either the rear pinion mount as seen in the diagram
70-81 F-Body Torque Arm Page 21
below or at the transmission crossmember until you have the correct angle and any driveline vibrations should
go away.
We have found that in all our installs we have not need to adjust the pinion as it is engineered into the mounts



Not sure how they don't find a need to run them at the center between that mount and the torque arm because mine would point down without these washers.

That would both the trans and center pointing downward. Many websites say this is not acceptable.

I do have an email out to them. The initial email mentioned removing shims at the trans. This doesn't seem correct at all.

I do have the old subframe setup with the very thin tube trans crossmember. Not sure if this has anything to do with anything, but like I said, I can't go any higher with the trans to reduce that downward slope.