So TREMEC has a nifty app out there called 'Tremec Toolbox' that among other things allows you to measure the driveline angles in a single plane. I have had this installed on my mobile for a while now and I finally took some time to put it to a test.

It basically uses the mobile device's angle finder function to add-up the various angles and determine whether your setup falls within the "acceptable" range of parameters. To be fair, they state quite readily that it only works within a small range of setups and if anything, it may report some final results that while quite functioning in real life the app according to it's design parameters finds questionable.

OK, so I did two things. I measured stuff out manually and then I did the TREMEC app calculation. Here are the results:

1) Transmission Angle
MANUAL = 2.5 deg down
TREMEC = 2.5 deg down

2) Driveshaft Angle
MANUAL = 5 deg down
TREMEC = 5.4 deg down

3) Pinion Angle
MANUAL = 0-0.5 deg down
TREMEC = captures the angle but does NOT display

OK, now comes the TREMEC result which shows:
'Driveline Operating Angle = 2.9'

The result is displayed in RED, meaning that the app does not think this is correct/good setup.

I've attached a diagram I drew to better illustrate these.

Given my understanding of what these angles say, I think I am in the 'OK' ballpark for a street driven car. The goal here is to be near 0 (same plane) reading between the pinion and trans angles when under power. So I am accounting for the pinion climbing up the ring gear by about 2 deg under WOT.

Quite honestly though I never understood this particular part about drivelines. I had previously installed a 6 deg axle shim kit to correct the really bad pinion angle which was a result of installing a '69 B-body 8-3/4 housing in my M-body ride without re-locating the axle pads/mounts first. This shim actually allowed me to point the pinion down by 6 deg to get me into that 0-0.5 deg angle.

So what do you guys think?