Questions to those running ford hp60's

Front obviously. I have access to either a 79 or an 81 hp60. I've been told the 79' has a long axle tube on the drivers side(6" before the cast section) and the 81' has a short one (3" before cast section). I am use RE LA's, I was told the 81' would hit the upper arm during flex when the pinion rotated and that it would be a tight squeeze to put a coil bucket on the short side. Question is which one did you guys use and why? How is it working? How is the oil pan clearence? Is there anything else I need to be concerned with?
Thanks in advance for the help