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Part of the confusion of pinion angle settings is that you are trying to take an educated guess at how much the pinion angle will change under load. The generally accepted change for leaf spring cars is 3-5* for auto cars and 5-7* for sticks. Obviously a high H/P car with soft springs will wrap the springs up more than a low H/P car with stiff springs, and a car with clamped front segments and/or slapper bars, Cal Tracs, etc may be only 1-2* deflection. And here's the rub - there's also u-joint operating angle to consider. And while on paper your car, with the trans pointing down 4*, you should need the pinion at 0*, so your leafs can let the pinion rotate 4* up to make the math for pinion angle work - that may leave your u-joints with no operating angle, (the engine/trans/driveshaft/pinion are all in line)and prone to fail from brinelling. That's why I mentioned that sometimes you have to change the engine centerline to correct the pinion angle. I'm sure there will be some that disagree, and this subject has been beat to death in the race forum. It may take several adjustments to get the whole package where you want it.

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Mr. Spirit,

A question for you so that I might learn no argue, are you saying on a street driven normal use street car you would set the pinion to allow for 4-5* wrap up on an auto and 5-7* on a stick? In the end at cruise speed I would think that the maintained torque/wrap would be the same for either one. Now in a holeshot/hard accel situation I could see the violent action of a stick wrapping up more and I could see a quarter mile car under constant accel until it's shut down sustaining a 4-5* wrap up. My specs were told to me long ago and I have set up many at 2* with no ill effects and to my knowledge never had to go back and adjust due to a vibration.

Thanks for your input.