A 9" Ford with a 32" tire has the pinion about 13" off the ground. Danas and 12 bolts will be higher. In a stock front end backhalf car, that has likely been lowered and with the engine and trans in the original location, the front u-joint will likely be lower than the rear. Typically in the stock location, the engine/trans will angle down front to rear about 2 or 3 degrees. In this situation which is very common, in order to make the pinion and tailshaft parallel requires the pinion angle to go positive which you just don't do. It is not unusual in these cars to end up with what is called the "broken back" configuration. Not the optimum set up, but many times you have to compromise and do the best you can with what you have. The alternative is to relocate the engine/trans mounts. If you are building a car ground up, these things are taken into account and positioned correctly, but in a stock bodied, back half car, you usually don't have the luxury of everything being in exactly the right place.
I'm not saying the parallel tailshaft and pinion configuration is wrong, because it is the most correct way to set the driveline up. I'm just saying that sometimes you can't get there and you can't set-up the pinion angle incorrectly to make it happen.
ok when you say the tail is lower, give me an angle on the trans? is the tail pointing up? how many degrees?
I know of NO factory installed engine, that points the trans up in the rear. What he is saying is the same thing I said....which IS, if the FRONT joint is LOWER than the rear joint(which is common) the shaft is obviously running uphill. And even if the trans and pinion were dead level the shaft is STILL running uphill.......soooo, if you set it up to try and achieve parallel angles, the pinion is GOING to be positive angle.......that's a no-no. Bottom line, if the front joint is LOWER than the rear joint and the trans is either level, or down, the theory of "equal angles" goes right out the window.......So I ask again, in THAT scenario, how are YOU going to set the angle, if you maintain the angles must be even.
And if your answer is that you have never seen a car like this............well then you haven't set up many cars, because this is a VERY COMMON scenario. Even my daily driver Challenger that sits low and has a 315 radial on the back, has the shaft running uphill in the rear. And we KNOW factory Mopars had an angle on the motors from the factory. Amazing that it doesn't toss driveshafts out on the road or rattle my teeth out I guess.
Monte
