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Discussion Starter #1
Got the engine back in the 63 finally. Trans is rebuilt and going in tomorrow. Question is: is it typical to have the trans yoke pointing down and needing to set the rear pinion upward on these? If I set it up opposite it looks like the trans will hit the tunnel.
 

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Not necessarily point AT each other. The engine will point down 2-3 degrees. It is ok to have the pinion at zero to -2 down to compensate for wrap in the leaf springs and then itll be close to pointing at each other under acceleration.
 

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Not necessarily point AT each other. The engine will point down 2-3 degrees. It is ok to have the pinion at zero to -2 down to compensate for wrap in the leaf springs and then itll be close to pointing at each other under acceleration.
What he said is the more accurate way to state it.. When accounting for axle preload.
 

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It's not so much which way the tail shaft is pointing, or the angle it's on. It's the working angle of the U-joints that matter. In other words, the angle of the driveshaft compared to the output yoke, versus the angle of the pinion shaft to the driveshaft.
 

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66 Chevy II, Pontiac powered; 68 &75 Firebirds
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Driveline angles are set a bit differently based on whether the car is mostly street or mostly strip.
For normal street driving the angular relationship between the engine, driveshaft, and pinion should be set so that the u-joints operate at an angle, preferably 1° to 3°, maximum of 5°, never 0°.
 

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Mike - 74 Nova Baltimore, MD
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Discussion Starter #10
Been working on the car as time has allowed.

Does the car need to be level? There is conflicting info on this. Or should I worry more about getting the trans and pinion opposing and not worry about the driveshaft angle, etc?
 

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It’s not absolutely necessary to be perfectly level but it would make it a little easier. If the vehicle sits with a rake lower in the front you will have to find to what degree.. Let’s say the car has a static ride height rake of 8 degrees lower in the front.. Subtract 3 degrees from the 8 degrees of chassis rake and you should be a 5ndegrees at the output shaft.. setting up the pinion is going to be a similar procedure. The thing to keep in mind is that the universal joints need to move a little bit otherwise they are unhappy. I’ve found that some chassis’ are setup from the factory with lateral driveline angles. The engine and trans sit at an angle to the frame rails cocked to the passenger side frame rail. I suspect there isn’t enough elevation change availabile front to rear so the chassis engineers put the angle in laterally..
 

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Discussion Starter #13
It’s not absolutely necessary to be perfectly level but it would make it a little easier. If the vehicle sits with a rake lower in the front you will have to find to what degree.. Let’s say the car has a static ride height rake of 8 degrees lower in the front.. Subtract 3 degrees from the 8 degrees of chassis rake and you should be a 5ndegrees at the output shaft.. setting up the pinion is going to be a similar procedure. The thing to keep in mind is that the universal joints need to move a little bit otherwise they are unhappy. I’ve found that some chassis’ are setup from the factory with lateral driveline angles. The engine and trans sit at an angle to the frame rails cocked to the passenger side frame rail. I suspect there isn’t enough elevation change availabile front to rear so the chassis engineers put the angle in laterally..
Ahh ok so this may get me somewhere. The car definitely has more rake to it after I changed the wheels and tires. Thanks!
 

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Discussion Starter #14
I noticed that in post #5 I posted the wrong link.
This driveline angle calculator from Spicer is really handy.

https://spicerparts.com/calculators/driveline-operating-angle-calculator

Just put your car on the (flat) ground and use a digital level on the tail housing flat, driveshaft tube and pinion yoke flat and enter the angles into this calculator.
I've tried the spicer calculator with the angles I was measuring and the only way I could come up with the 1-3 degree operating angles was to have both the trans yoke and rear pinion pointing down. And obviously that is going to lead to issues sooo :confused:
 
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