Thanks for quick reply- Yes I was told this is from a stock mustang 2. The first part of your desciption seems correct, the lower arm fits between the crossmember, but nothing runs up on an angle, the top arm operates parallel to the lower one. The lower one is 13 " long-pivot to spindle mount- the top one is shorter. The width of the new lower one is 10.5", thats at the end that mounts to the crossmember.
All the measurements look correct with the new set, except were the lower one connects to the crossmember, it looks like it mounts on the exterior of the crossmember, instead of the inside like the one on the car.
Hope this explains it better. Thanks Rod