ive done several frame shortenings...leaf spring trucks are easy....I always make a straight cut and then reweld..some do step cuts..I usually add a piece inside the frame lip and a diamond over the weld on the outside
I always cut in the straight section of the frame...in front of the spring hanger
2wd and 4wd leaf trucks are the same process...
heres another way...
http://67-72chevytrucks.com/vboard/s...d.php?t=123624
and heres a video.....
https://www.youtube.com/watch?v=6o2k...B_ZjfdtUZEO2Po
there are also bolt on kits to do this as well but I prefer welded much much more...
I always use matabo style blades to cut with....leaves a nice clean edge