Thanks fella's.
Well, the process is really quite simple on this one. Because the parts are large enough, I can use the big buffer with the 8" wheel. And lots of brute force.
To preface, on smaller engines like the Saito and OS singles I have done, I will use a combination of needle files, and progressively finer cloth backed abrasive rolls until they are very smooth. Then I use a Dremel with a cotton buff and polishing compound.
On this FS400AR I simply use the big buffer with brown Tripoli buffing compound and go to town on it. The brute force of the big wheel, speed, and compound polishes the parts without needing to sand them first.
(Caution must be used, however. Because this thing will grab parts out of your hand and fling them so far you never will find them. Sometimes it will grab a part and when it flings it, it hits the ground first and damages the part. Now that I have learned about these dangers I have moved the buffer so it is against the wall of my shop. At least the parts can be found if they get grabbed out of my hand. 
)
Anyway, I just keep applying compound to the wheel and holding the part against it until it shines.