[dirtyjim]

you may be able to use the 85 spindles and keep the original centerlink by using astro van inner tie rods with the 85 outer tie rods and 85 or astro tie rod sleeve.
I haven't verified that it will work yet but from what I've read and the sizes I looked up the astro tie rods will fit the 67-70 centerlink , their threads and length are the same as the 73 up inner tie rod

I would also use the brake lines and prop valve from the 85. you'll have to drill the holes in the front crossmember for the prop valve and the holes in the frame for the front brake hoses to pass through but then you can use 73 up front brake hoses instead of the adaptor hoses. the 85 rear brake line from the prop valve should go all the way to the union on the frame under the cab.

while you working on it I would also replace the lower a-arm u-bolts if they haven't already been replaced.