How important is correct drive shaft angle?
what is the correct angle and why?
I recently put a spacer between my tranny tail shaft housing and the crossmember to bring the tail shaft up a bit (1/2") in an effort to level my motor (bring the front of the motor down)
The straighter the better, I don't know what the limit is though. The most important part is that the angle on the pinion be as close as possible to the angle on the yoke to avoid stress and vibrations.
The more angle you have the more stress is put on the driveline. The u-joints in particular. It also increases the chance/severity of high-speed shaking do to the driveshaft walking around the U-joint.
I'd install a driveshaft safety loop and give it a try. If you find your breaking u-joints then you could look at turning the rear axle a little.
I think I have read that the optimal is 2 degrees down ant the tranny. Try to get the tranny to that level and then measure the angle on the diff. They need to match or vibrations will occur. There are shims at Summit or jegs. I just used large washers until I obtained the proper angle and then welded them to the perch.
how do I go about measuring to see what angle I currently have.
Is there some sort of magnetic gauge I can just stick on the driveshaft and read the needle?
yep, use a magnetic angle finder. I wouldn't be too worried about driveshaft angle, it can only be so bad in a car that sits as low as a mustang. Pinion angle, however is important. You want the pinion to be 2 or 3 degress downward from the angle of the driveshaft. If you know your geometry, lets say the driveshaft is 5 degrees down from horizontal. You'd want the pinion angle to be 7-8 degrees below horizontal.
How important is correct drive shaft angle?
what is the correct angle and why?
I recently put a spacer between my tranny tail shaft housing and the crossmember to bring the tail shaft up a bit (1/2") in an effort to level my motor (bring the front of the motor down)