I want to do a SOA conversion on my 1978 Scout II.  I have read about pinion angle.  Some say you need to grind welds off the axle tubes, and twist what I believe is the steering knuckle around a few degrees.  Some say you just need a drop pitman arm to keep the steering geometry the same.  I would be gaining about 4 inches.  Any help would be appreciated.  Thanks.  

This will give you more than 4 inches because there is axle thickness and also spring pack thickness because you will be rest on bottom of stack on axle rather than top of stack on bottom of axle. Weld new perches on and leave old ones be and clump U bolt around axle with plate for Ubolts on top of springs. A bigger concern in drive shaft angles. You need to get CV's installed in both ends of them (front and rear shafts) because it will have vibration issues and short Ujoint life otherwise. You could twist pumpkin up a bit and reweld but you still really need CV's. You well have to modified steering too to restore geometry.  

I have read a lot of your reply's to questions.  You mention CV's on driveshafts a lot.  The only CV I know of is constant velocity joints.  I was under the impression that this is the same as a u-joint.  Could you explain CV's on driveshafts?  Thanks.  

A CV is not a Ujoint. A Ujoint does not have a constant velocity across it as in bends (the further it is bent the more the velocity changes) and it actually speeds up and slows down twice per full rev. (this is why lifted trucks can vibrate on shaft) A CV it designed to maintain a constant velocity across it at any angle. Rather than me explaining it further, if you use link I found for you below, Wikipedia will give you more info and a few pictures too.

Click Here  

Thank you.  Makes sense now.