opinions on pinion/driveline angle

[LJ67barracuda340]

I'm asking for opinions on whether I need to change my pinion angle and how much. I measure the trans 5* down and the pinion 5* up. I'm thinking under heavy load that the pinion angle would be too high. I've got a 7 leaf rear springs with the top and the added leaf that are full length. I don't think they will wind up much being that short and that much steel.
The car is a cruiser not a drag car but we still like to have fun with it.
67 Barracuda, 340, 10.1, Edel heads, 545/555 roller cam, 3;23 gear, 5 speed. ~400+ hp I think.
I have a 4* shim in there and I was thinking of reducing it to 2*. I don't know how much angle the pinion angle might change under power or cruising.
I don't want to use a pinion snubber near the floor or lots of clamps or Caltracs, I'm after a stock look.
Am I over thinking it,,,what do ya think??

 

[67Dart273]

If you stated this correctly, the trans and pinion are now at zero degree relative angle. The pinion is going nowhere but up under accelleration and THAT is where the two should be parallel, zero angle. "So yeh" I'd say you need to go 2 --2 1/2 down

 

[CUDA69]

What is the angle between the trans and drive shaft and the rear and drive shaft? For highway cruising try for less than 3.5 degrees and get them close to the same, but the rear up and the trans down. This is not for super hard launches though.

 

[LJ67barracuda340]

What is the angle between the trans and drive shaft and the rear and drive shaft? For highway cruising try for less than 3.5 degrees and get them close to the same, but the rear up and the trans down. This is not for super hard launches though.

Thanks, I realize the trans up 5* is not the best but I have an aftermarket 5 speed trans and it is very close to the floor now. If I cut the tunnel bigger I wont get the stock console over it. My thinking is split the difference kinda without inducing a vibration cruising but making everything happier on hard launches. So I guess I'll be at 5* up and 2* or 3* down cruising. The drive shaft is out now but I'll check the angles later, memory says a protractor on the shaft the way it sits read 0*

 

[TrailBeast]

There is a free Tremic app for driveline angle measurements.