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Discussion Starter #1
Trying to get this right so I can get my drive line ordered. Forgive me if I get the terms wrong. The way I understand it is I measure the vertical angle of the rear face of the transmission and the vertical angle of the pinion on the rear end (where the drive line bolts on). I then put spacers under the transmission mount to get as close to the same angle on both. And am I correct that I don't worry about the fact that the shafts are not in line. They are offset side to side.

If I put a 1" spacer under the transmission mount the angles are the same. Is this to much? If I use a 1/2" spacer it gives me about 2 degrees difference.

There are a lot of posts on this subject and this is what I got from reading them. So much great information here just trying to sift though it. Thanks
 

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There is no issue with IRS and pinion angle. Just install it. Move the trans so the headers fit right, up or down a little.

Pinion ange is more important on a live axle car so do not sweat it on an IRS car.
 

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And am I correct that I don't worry about the fact that the shafts are not in line. They are offset side to side.
Why???


I tried to make my driveshaft as straight a shot as possible. Both up + down + sideways (T56, I had to move the diagonal bar on the passenger side transmission tunnel).


In theory you'd like to have maybe 1-3 degrees (vertical) on each end to keep the u-joints moving + lubed. But when you're dealing with limited space and a 10" driveshaft...

So I made mine as straight as I could get it.


Mike
 

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Move the trans so the headers fit right, up or down a little.
Good point - much more important to get the headers / sidepipes point in the right direction...

You'd better watch the side to side (header / sidepipe) alignment if your tranmission is not pointed at the pinion.


Mike
 

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x2 what Richard said, I also had to raise mine so the oil pan was not below the frame rails as in NJ this would not pass inspection. Something to keep in mind depending on your state requirements.
 

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Discussion Starter #6
ok so I'm looking at the wrong thing. Don't worry about the pinion angel. Try to get the driveshaft strait. Check

I am going with under car exhaust and its not made yet so I don't have the same worries with header and side pipe alignment.

I do have the issue of the oil pan too low. The drain is about 3/8" below the frame. Didn't think about the state not liking that. I don't like the oil pan being so low but not sure the best way to fix that. I used Mike Forte's engine mounts. if I move them much more I might as well make my own. they are half way forward on the frame mounts to get any clearance. If I add spacers to raise the engine so the oil pan clears then they are going to only have about a 1/4 on the frame mounts. This 428 is tight.
 

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ok so I'm looking at the wrong thing. Don't worry about the pinion angel. Try to get the driveshaft strait.
You don't want the driveshaft straight, you want it somewhat close so the bearings keep lubed. You don't want it perfectly straight as others have mentioned.
 

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Don't spend a lot of time trying to make it straight, it wasn't meant to run like that anyway. On IRS the pinion angle never changes. Follow Richard's advice.

Frank
 

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Darren: Even if the IRS driveshaft is level in the vertical plane it is offset slightly in the horizontal plane which keeps the u-joint bearings moving. Mine is level in the horizontal plane in my coupe. As it worked out the side pipes very close to level.
CB
 
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