I haven't done the swap yet but I'm planning on it. I've done some measuring and comparing and even though the '88 and up rotors will physically fit on the '87 and older spindles, I don't believe you can get a caliper to fit.
According to the thread in the FAQ's here on the board, the '88-'98 or so spindles need to be used with the '88 and up rotors. Then you'll be able to use the calipers from the same vintage spindles and rotors. I would suggest checking out the write up...it has all the info to do the swap.
http://www.67-72chevytrucks.com/vboa...ad.php?t=35042