Ford manuals show use of a brace that goes between the frame rail and the upper control arm to hold the arm up when the shock has been removed.  A wood 2x4 will achieve the same thing, but that brace is not necessary on 65-73 IF you still have the shock absorber bolted up.  The shock will hold the upper control arm up.  Removal of the spindle (upper ball joint) from the upper control arm will not affect anything to do with the spring or upper control arm.  You can even do it without the shock holding the UCA up, but it is a little more difficult due to the angle of the ball joint at that point.

I have never had the need to use the brace, ever.

I am guessing that you have a 65-73 Mustang.  If not, disregard this answer.

Jimmy sent me a PM on this.  Its a 65 mustang.  He's swapping out 6 cylinder spindles for 8 cylinder spindles. He is putting in a v8 in the future. Ok experts, go ahead and give him his answer. 

My .02 cents:  if you have 6 cylinder spindles,  you probably have 6 cylinder springs. They would need to be replaced anyway, so I would remove shocks, then springs, then spindles, and then while your at it...........

It is alot more important to install V8 steering linkage with V8 spindles than it is to change out the springs.  Six cylinder springs are not that much different than the 289 springs to begin with.  I know of several cars that ran 6 cylinder springs with a 289 or 302 and had no issues.

If you run six cylinder steering linkage with V8 spindles, the bumpsteer is downright scary.