axel housing perch location

When I installed my B body rear in my car I had to move the perches.

What I did (be it right or wrong) was to put a straight edge on the existing perch and etched a line on the axle tube inward toward the center. Then I cut the old perch off, placed the new one on using the line, and tacked it. Did the same thing to the other side. Once I had them tacked, I checked my measurement to be sure I had the 43" on center, and welded them up.

I have had it in my car for two years with zero vibration issues under light throttle or to the floor.

Basically by doing that, I followed the factory pinion angle, and luckily it worked out, lol.