http://www.chevyk5blazer.com/forums/showthread.php?8385-the-disc-brake-conversion&highlight=Rear+disc+brakes
Some did it on another forum with a picture
http://www.ebay.com/itm/Weld-On-Chevy-12-Bolt-Rear-Disc-Brake-Conversion-Kit-/252324660283...
Shouldn't need anything else. A raised steering arm is usually the first choice, than a dropped link. You are doing it in the least desirable way, with the pitman arm.
i had crap seats in my 75, came across some ford ranger truck seats probably late 90s. they had adjustable head rest, they just pulled right out, so it gave it the low back look.