Pinion angle

Jcmitch3

Active Member
#1
So, I have finally gotten the 9.3 olds all bolted up under my Biscayne. This is my first foray into setting the pinion with a 2 pc. drive shaft.
Am I right in assuming that i can use the "same but opposite " rule with the 2pc? IE, right now I have 3.5 down on the trans...can I set the pinion at 3.5 up ( or take out a degree or two to compensate for the rise under power) and call it a day?
 

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64ss409

Well Known Member
Supporting Member 9
#2
So your pinion centerline is parallel to your crankshaft/transmission centerline, that sounds right. As far as taking some out on the pinion angle for launch torque, I'll someone else respond to that.
 

409gang

Well Known Member
#4
So, I have finally gotten the 9.3 olds all bolted up under my Biscayne. This is my first foray into setting the pinion with a 2 pc. drive shaft.
Am I right in assuming that i can use the "same but opposite " rule with the 2pc? IE, right now I have 3.5 down on the trans...can I set the pinion at 3.5 up ( or take out a degree or two to compensate for the rise under power) and call it a day?
Gotta love those 57-64 Olds/Pontiac 9.3's!! I put mine down 3 degrees for launch but that is in a race car with a 4 spd, the pinion will try to climb the ring gear. I would think it would be the same for a 2 piece drive shaft, its the difference in angle of the pinion centerline and the drive shaft centerline. Make sure when checking that you have the suspension loaded (jack stands under axle). I would also put stands under the front of the car to make it somewhat level as it might change the load on the rear suspension.
 
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61BUBBLE348

Well Known Member
Supporting Member 9
#7
On launch and under hard acceleration the pinion lifts up.

On the street, I typically set the engine at 3 degrees up at the front and have the pinion 3 degrees up at the front, this is with a single piece tailshaft. In general you can be around this and for longevity matching the angles is the right fit. A friend has a 64 Bel Air with a blown small block, PG and 9" and he runs the engine approx. 2 degrees up at the front and the pinion 1 degree down at the front, this car never (rarely) sees long distance hauls.
 
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