I made two cuts on the crossmember at the same angle of the driveshaft tunnel and used a air hammer to cut the spot welds on the floor pan took about 15 min tops.

69 Dart swinger 417 W8 Liberty 5 speed
6.03 @114/9.49 @141 on motor 5.30 @131 on juice 1/8th mile 28x10.5's at 3200lbs
70 Challenger RT 440 4-speed 4:10 Dana

http://www.youtube.com/watch?v=VowFy4nDdfI