I am setting the pinion angle on my car, it is a leaf spring car, so I am looking for 7* nose down. My angle finder is reading 3* on the tail end of the drive shaft and 10* on the pinion nose down. This is my 7* correct?

If there is a V at the pinion yoke and the driveshaft then yes that is the angle, if it is an inverted V(I can't make that sign on this keyboard ) then make it a so the driveshaft is the left side of the V and the pinion yoke is the the right sid of the V, both pointing at the bottom of the V I really hope this makes sense BTW, if the car vibrates under WOT or on deacceleration try 5 degrees difference next time Some cars will vibrate at 7 and some don't I think it depends on the U joint size used.

Put your angle finder on the yoke. It should be 5-7* down.

do a search on pinion angle, that will answer all of your questions

A true 7 degree negative pinion angle will usually bind.

I recommend 5 degrees, maximum.

Make the pinion parallel to the transmission as a baseline, then roll the pinion downward 4 degrees and weld the perches. This will yield a true 4 degree negative pinion angle.

I put a Dana in my car and went for a ride and it had a bad vibration when I decelerated. I checked pinion angle and found it to be 10 degrees nose down. I shimmed it to 3 degrees nose down and it was fine.