driveline angle odd or is it me?

[crash340]

Guys, I had my car (73 Cuda) up in the air yesterday and thought I'd measure the driveline angles as Im building a Dana for it.

So with jack stands under the diff housing, I used an engineers square on the harmonic balancer to set my electronic digital angle gauge to zero ( so now I have my gauge zero'd parrallel to the crankshaft, I then checked my driveshaft, its rising(going up) 2.3* from the trans, then my pinion angle is a down 2.3* from my driveshaft.

How many others have driveshafts that go up rather than point down?

[Bullitt-]

found this on moparts... sounds like your rear needs to point up if I read it right

[Chryco Psycho]

this is the best situation so your car sit low & the driveshaft climbs allowing nose down on he diff , perfect 

[crash340]

So, the diff that is in it at present is an 83/4 69 B Body, Ive had to put 3* shim under the spring pads to rais the nose of the pinion to what it is now, and match the original E Body pinion angle. I have not lowered the car any, it may have sagged a small amount from original but it would only be a small amount. As indicated I'm building a Dana 60 for it and will need to weld on new spring pads, do I simply need to match the original E body housing angles??? Do I also need to shim the rear of the trans up a little??, right now I have somewhat similar to the lower right image of the post by Bullitt, Under load it will raise the Pinion angle and be Ok as Neil indicates but Im confused a little on this sorry.
This is what I have now if it helps.

[Chryco Psycho]

OK I misunderstood . can you raise the rear of the Trans ?

[crash340]

Im pretty sure there is enough room above the trans, I do know there are no shims between the trans and the mount. I'll have to re do my exhaust if I rais the trans but I had planned on doing that in any case as the X pipe is too high and I cant let the rear wheels hang without stressing the pipe due to the driveshaft hitting the X pipe.

Right now Im just trying to work out spring perch angles to set them up on the Dana, Im thinking I'll just set them at the same angle the original diff housing had them at., then once the diff is in sort out the pipes and trans angle.

[GoodysGotaCuda]

Use the Tremec transmission app and your smart phone, it will help you ensure the measurement is being done correctly.

http://www.tremec.com/menu.php?m=154

[Racer57]

Use the Tremec transmission app and your smart phone, it will help you ensure the measurement is being done correctly.

http://www.tremec.com/menu.php?m=154

That app is worth what it costs. To get accurate readings a person needs to at least use a digital level.

[crash340]

And thats exactly what I was using, a digital level, I downloaded the app, and it read the same

[1 Wild R/T]

To simplify things forget the drive shaft.... You need to look at the crank centerline and the pinion centerline... Realize as power is applied the nose (front) of the pinion rises... The amount depends of your springs & how much power is being applied... But as a rule going down the road expect about 1.5-2 degrees of rise.... You want the crank centerline & the pinion centerline to match when your running down the road.... So static setting you want the pinion 1.5-2 degrees less than matching the crank..

[crash340]

Ok, right now I'm at about 4.6* nose down from the crank c/l. Thats with a 3* shim under the spring perch's to raise the nose as the B Body housing has more nose down than an E body. Again, if this is the case it points to the trans mount needing shimming to lift it by the sound of it,

Im thinking I'll just match the std E Body spring perch angle when it comes time to weld them to the Dana, I know most people say put the diff in and tack the perch's in place one angles are set but this is going to be a pain in the a@@ for me. to match the E Body diff that came out of it will have the pinion angle set pretty darn spot on if I raise the rear of the trans.

[brads70]

FYI there are bolt on spring perches . Just be sure to weld them when your done.
http://www.summitracing.com/int/parts/aaf-all56127/overview/

[dodj]

Again, if this is the case it points to the trans mount needing shimming to lift it by the sound of it,

When I first took the trans out of my car, back in '85, I didn't understand what the 1/8" thick rectangular 'washers' were doing on my rear trans mount. So I didn't put them back. It was years later when I found out why they were there.    Maybe someone did the same with your car.

Once you 'get it', driveline angles are easy to understand. But with all the opinions and misinformation on the web, it becomes a very confusing subject.

[Racer57]

What confuses the hell outta me when talking about getting the proper angles within a degree or two, is thinking back to the days when we ran air shocks with the azz ends jacked way up and didn't have any vibration !!

[Cudakiller70]

What confuses the hell outta me when talking about getting the proper angles within a degree or two, is thinking back to the days when we ran air shocks with the azz ends jacked way up and didn't have any vibration !!

In high school a friend had a 69 SS 396 chevelle 4 speed, super clean car. First thing he did was put gabriel hijackers on the rear and pumped them up. I don't think he could have raised the rear end any higher, they were maxed out. He pounded this car all the time and yet never one problem.