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Discussion Starter #1
Trying to get things straightened out and one of the things I don't know is whether the center of the front of the crankshaft should be at the same height as the center of the tailshaft. I have the car sitting level on jackstands currently and decided to measure center of tail and center of front of crank, looks like the crank is sitting 4" higher than the tailshaft.

I'm using solid mounts on the motor and a factory rubber AOD mount on the powerglide trans with factory crossmember under the trans. I have the motor lifted a little off of the factory k-member mounts because the pan was hitting the steering rack. I can make a custom mount for the trans to raise it a bit if need be.

As it sits, the driveshaft is perfectly level with the ground and I have the rear pivoted down -3 degrees for pinion angle. I still have rubber bushings in the upper arm mount on the rear end. Everything else is solid. Its a 9" rear and powerglide trans.
 

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Every car is going to register different measurements. What you want to do, is point the transmission tailshaft at the pinion on the rearend. Make sure the weight of the car is on the rear shocks while doing this. You want everything the way it would as the car was sitting on the ground. Good luck.
 

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Discussion Starter #3
That is how I measured. All 4 tires are on cinder blocks measuring right at 7.5" off the ground for each tire. The only weight difference is that I'm not sitting in the drivers seat. When I jacked up the front, and rear, I made sure to push up and down several times on the car to level out the suspension.

I'm just curious basically if the tailshaft of the transmission should be level with the center line of the crankshaft. In otherwords, imagine a straight bar passing through the crank all the way to the tail shaft. Should this be a straight line? If it should, does the motor and trans need to sit level with each other or can it be angled downward from the crank pulley to the tailshaft? If it can be angled, how much and what would be a correct angle? Now take that bar and go all the way to the rear end driveshaft pointing point, does that need to be straight as well?
 

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Discussion Starter #4
Here is something else I'm thinking of making to resolve the issue of the Moser 9" housing upper ctrl arm mounts. These brackets would sandwhich the mount that is on the rear currently allowing me to mount the ctrl arms lower on the rear side to bring instant center up (less downward angle on the arms).

 

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The angle of the motor to tailshaft is basically irrelevant . Make your manifold sit level or slightly down (1 to 2 degrees) . The important part of the alignment is to have the output shaft of the transmission pointing directly at the pinion centerline . Hight difference between them is necessary to get bearing roll in your u-joint or you will burn them up .
 

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Discussion Starter #6
OK, thanks for the info. Someone at the track told me that the car would sixty foot better if I lowered the engine down. Right now I have spacers under the mounts because of the oil pan hitting the steering rack. I've got a factory manual rack with the thick alluminum housing. If I were to get a flaming river rack, I could probably sit the motor down on the mounts.
 

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With the motor up higher, you will be more prone to wheelstands. That may be what they were referring to at the track.
 

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If I read your first post right the pinion angle is way off. Since the engine tranny is pointing down the pinion should be pointing up to keep the u-joints parellel.
 

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Discussion Starter #9
If I read your first post right the pinion angle is way off. Since the engine tranny is pointing down the pinion should be pointing up to keep the u-joints parellel.

I'm not sure what you mean.

currently, the driveshaft is sitting level with the ground with everything loaded, ie all 4 tires are up on bricks that are 7.5" tall. That said, if engine/trans is angled downward, the angle coming out of the trans in relation to driveshaft should be a V, the same as the angle from the driveshaft to the rear yoke should be a V.

Are you saying that there should be no angle between the driveshaft and the rear yoke? IE zero degrees?
 

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Your crank shaft center will be the same as your tail shaft center. Yes. Setting pinion angle can be done many dif, ways. This may help http://www.wolferacecraft.com/instructions.aspx The trick is to have a negative pinion angle from the tail shaft / crank shaft angle. If you were to take an angle finder and place it on your crank ballancer is will be the same as your tail shaft. You need to watch the angle finder when measuring all 3 points (Tail shaft, drive shaft and pinion) if the angle is left of the 90 or right of it on your readings and subtract the numbers to get the negative. Also you need to have the car ready as if you were going to make a pass, Your weight in the seat, fuel, air pressure exc...
Hope this helps.
 

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I'm not sure what you mean.

currently, the driveshaft is sitting level with the ground with everything loaded, ie all 4 tires are up on bricks that are 7.5" tall. That said, if engine/trans is angled downward, the angle coming out of the trans in relation to driveshaft should be a V, the same as the angle from the driveshaft to the rear yoke should be a V.

Are you saying that there should be no angle between the driveshaft and the rear yoke? IE zero degrees?
What you want when the driveline is under power is for the u-joints to be parallel.
Driveshaft being parallel to car does not mean much.
LIke I said if engine/tranny is pointing down then pinion should point up a bit to allow some movement and let pinion angle be positive under load.
 

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Discussion Starter #12
What you want when the driveline is under power is for the u-joints to be parallel.
Driveshaft being parallel to car does not mean much.
LIke I said if engine/tranny is pointing down then pinion should point up a bit to allow some movement and let pinion angle be positive under load.
Well, then it will be or at least close to it under load. That is the reason for the -3 pinion angle. I have factory type rubber bushings still in the upper ctrl arm housing on the rear end. So as they give a little bit under power and the rear end trys to twist upwards, the DS and rear will essentially be parallel.
 

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Well, then it will be or at least close to it under load. That is the reason for the -3 pinion angle. I have factory type rubber bushings still in the upper ctrl arm housing on the rear end. So as they give a little bit under power and the rear end trys to twist upwards, the DS and rear will essentially be parallel.
6 degrees is a long way for the pinion to go but you would only be a few degrees away at worst so it will work.
 

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If the drive shaft is pointing down then the pinion does not need to point down as much -3 with rubber mounts is cutting it close dont go under to start with. Just so it keeps negitive

As for a drive shaft pointing down, so the pinion points up, this is not the way to set up a car, the pinion will climb on launch and make a postive angle ( the way you describe) even worse.

Pointing the tail housing at the pinion and adjust from that on the rear u-joint, the drive train needs to be angled correctly for the application and a wedge plate will take care of a carb issue if there is one.
 

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Discussion Starter #15
Let me clarify. The current pinion angle between driveshaft and rear end yoke is -3 degrees. With the car on jack stands, tires all within 1/2 of each other off the ground (front tires on bricks, rear end on stands), the driveshaft was at 0 degrees and the rear was at -3 degrees. Giving -3 pinion angle which is the desired for factory type rubber bushings to make up for bushing give.
 

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i think with the stock type bushings you will be fine the only thing to really watch for is a high speed vibration on deceleration. because it will pass -3 on the big end. If the car hooks good and no problems when you let off dont worry with the numbers just my thoughts
 

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I am going through the exact same thing now. My tailshaft is pointing down and the driveshaft is actually going up to the rear yet it is parallel to the ground. I have a 6 degree angle on the front u-joint but had about 0 degrees on the pinion, so on the big end after letting off I had a bad vibration since it was throwing the pinion down on decel. So now I adjusted the pinion to about 4.5 degrees up. That way when I launch it should make the two angles (tailshaft vs pinion) parrallel. I have all solid control arms so there is not much deflection. Heading to the track tonight to see what happens. Eventually I will probably get dropped motor mounts to make the engine/trans sit more level , then readjust rear end angle. Good Luck
 
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