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Install shims b/t the spring perch on the rearend housing and the leaf spring.
Tapered shims and Jegs and Summit have lots of them. Just did this on my brothers car two weeks ago and it makes a big difference when you get the angle correct on a leaf spring car. 
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You should have nose down on the diff so as you load
it it goes to straight under full load... leaf spring
cars need more due to wind up on the springs... if
its a street car it requires less than a drag car, so
about 5* for a street car and about 7* for a drag car
look at the video of the rear diff in action and you will see why. 
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When you are doing all of that don't forget to also check the angle of your rear spring shackles drivers side needs to be @ the 10:00 and the passenger side @ the 2:00 o clock position.
Quote:Move the upper mount forward so you get a good angle (I like at least 30 degrees forward from the spring to the upper shackle mountQuote:
When you are doing all of that don't forget to also check the angle of your rear spring shackles drivers side needs to be @ the 10:00 and the passenger side @ the 2:00 o clock position.
Mine basically go straight up. I do have another set of mounting holes that are at about 10:00 and 2:00.
) sitting still with the chassis loaded.
Quote:What he said^^^^ you want opposing u joint angles under full power so if the trans is 2 degrees down you want the diff 2 degrees up under load.
Pinion angle is the relationship between the pinion centerline and the transmission centerline. It is not relative to the ground nor to the angle of the driveshaft.
Ideally, you want the pinion to become parallel to the transmission under a load, so you point the pinion downward a few degrees when the vehicle is resting on its suspension to compensate for pinion wind-up.
In other words, make the pinion parallel to the transmission as a base line, then roll the pinion downward 2-4 degrees and weld the perches. This is how a 2 joint driveshaft is designed to work.
Quote:Quote:What he said^^^^ you want opposing u joint angles under full power so if the trans is 2 degrees down you want the diff 2 degrees up under load.
Pinion angle is the relationship between the pinion centerline and the transmission centerline. It is not relative to the ground nor to the angle of the driveshaft.
Ideally, you want the pinion to become parallel to the transmission under a load, so you point the pinion downward a few degrees when the vehicle is resting on its suspension to compensate for pinion wind-up.
In other words, make the pinion parallel to the transmission as a base line, then roll the pinion downward 2-4 degrees and weld the perches. This is how a 2 joint driveshaft is designed to work.
What do you mean by "two degrees up"?
Quote:Quote:Quote:What he said^^^^ you want opposing u joint angles under full power so if the trans is 2 degrees down you want the diff 2 degrees up under load.
Pinion angle is the relationship between the pinion centerline and the transmission centerline. It is not relative to the ground nor to the angle of the driveshaft.
Ideally, you want the pinion to become parallel to the transmission under a load, so you point the pinion downward a few degrees when the vehicle is resting on its suspension to compensate for pinion wind-up.
In other words, make the pinion parallel to the transmission as a base line, then roll the pinion downward 2-4 degrees and weld the perches. This is how a 2 joint driveshaft is designed to work.
Quote:I completely disagree with the Rossler charts, Mopar engineers, more than one engineer
Yeah it goes against the Mopar chassis book I know. If your tailshaft is pointing down,they almost always are, in order to make the pinion parallel it will need to be nose up when loaded. When you set it how a driveshaft is supposed to be set with opposing angles at each end it almost always will not look like the diagram in the chassis book unless you're running SS springs. Like Cass said its all about the pinion in relation to the transmission not the pinion in relation to the driveshaft. My car is low and the driveshaft angles upward out of the trans although it still angles down in relation to the ground and my pinion angle is .8 degree nose UP at rest and should be about 3 degrees nose up under load which would put it parallel with the trans. ..... http://www.rosslertrans.com/Pinion%20Angle.htm
) spent countless hours researching and developing the results printed about setting the Moapr drag racing chassis up WITH leaf springs back in the day, 1962 to 1973 or so A standard Mopar A,B, E body will work very well set up using the Mopar bible on a leaf spring car, a ladder bar or four link leaf spring car with a floater or slider will work very well with 1 to 2 degrees nose down in relation to the dirve shaft, the pinion angle is not dependent on nor should it be set up off of or on the trans angle, especailly on a drag car that is set up for a lot of upward front and rear suspension travel 
A tube chassis car is a completely different animal than a standard Unibody Mopar car 
All U joints need a difference in angle to operate, it doesn't matter if it is up, down or sideways, it needs the angle to make the needle bearings rotate around the shafts and inside the bearing cups instead of sitting still flattening them out like they would if the pinion shaft and driveshafts where perfectly aligned all the time BTW, one of the first ladder bar cars I drove had negative pinion angle, probally right at 2 degrees nose up in relation to the drive shaft angle, I reset it so it had two degrees nose down in relation to the drive shaft, which was on a up angle to the trans, the trans was higher in the chassis than the pinion shaft was in relation to the ground. The stupid car ran exactly the same 60 ft. times and all the rest of the way down the track where same, my mind felt better though 
It never had a driveshaft or U joint issue after that 
Quote:Quote:I completely disagree with the Rossler charts, Mopar engineers, more than one engineer
Yeah it goes against the Mopar chassis book I know. If your tailshaft is pointing down,they almost always are, in order to make the pinion parallel it will need to be nose up when loaded. When you set it how a driveshaft is supposed to be set with opposing angles at each end it almost always will not look like the diagram in the chassis book unless you're running SS springs. Like Cass said its all about the pinion in relation to the transmission not the pinion in relation to the driveshaft. My car is low and the driveshaft angles upward out of the trans although it still angles down in relation to the ground and my pinion angle is .8 degree nose UP at rest and should be about 3 degrees nose up under load which would put it parallel with the trans. ..... http://www.rosslertrans.com/Pinion%20Angle.htm
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Yeah it goes against the Mopar chassis book I know. If your tailshaft is pointing down,they almost always are, in order to make the pinion parallel it will need to be nose up when loaded. When you set it how a driveshaft is supposed to be set with opposing angles at each end it almost always will not look like the diagram in the chassis book unless you're running SS springs. Like Cass said its all about the pinion in relation to the transmission not the pinion in relation to the driveshaft. My car is low and the driveshaft angles upward out of the trans although it still angles down in relation to the ground and my pinion angle is .8 degree nose UP at rest and should be about 3 degrees nose up under load which would put it parallel with the trans. ..... http://www.rosslertrans.com/Pinion%20Angle.htm
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If you`re on multi leafs you want more like 5-7 nose down............
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If you`re on multi leafs you want more like 5-7 nose down............
Yes, OEM replacement leafs + 1 helper leaf per side.
So unless I'm reading it wrong, going from what I measured, I should currently be at 3* down, correct?
Since most suggest between 5*-7*, lets say I go with 6* since it's a street/strip car.
Then 3* shims are what I need to install to get me there, correct?
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If you`re on multi leafs you want more like 5-7 nose down............
Yes, OEM replacement leafs + 1 helper leaf per side.
So unless I'm reading it wrong, going from what I measured, I should currently be at 3* down, correct?
Since most suggest between 5*-7*, lets say I go with 6* since it's a street/strip car.
Then 3* shims are what I need to install to get me there, correct?
In your video it looks almost like 0 then goes UP not good. Throw a 4 degree shim in there and redo a vid and post it.
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Can`t see the trans angle but the diff goes up past 0 under load. Put it back in the air, measure trans angle, figure what shims needed to get 5 down and go from there.
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No the top pic that says "Correct pinion angle" is correct. You want the trans and pinion centerline level at the same angle but paralell each other like the top pic as they should not be the same line. Once you get both the trans and pinion at a level 0 degree angle then you nose the pinion down the amount of downward pinion algle you want (2 to 7) so that way when you hit the gas and the diff wraps upward you will have both lines basically about paralell to each other as in the top pic that says Correct pinion angle. They build the cars with the rear lower then the trans and you need some angle in the driveshaft to make the U-joints work and stay lubed. If the shaft was dead straight the U-joints would not work and they would not keep lubing. Ron
Hope he figures it out............ 
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Its simple. Shim the trans to get its centerline level at 0 degrees and then shim the rear to the downward degrees you want to run from 2 to 7 down. I always like to get the trans level at 0 first if I can and then once the rear (pinion) centerline is level you know to nose it down to the degrees you want. Myself I feel its easier for most to work with it if the trans centerline is 0. Ron
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measure the damper or front pulley,then subtract 90 degrees
