69 340 k-frame and power steering questions

are the upper control arms 6/8 the same
yes

,i bought a 6 cyl box before i decided to go v8 ...are they the same
yes

i know the ps/man columb are different lenths ,buy how much , is there an easy way to tell ??

There is an adapter that makes up the length. I can go measure it on my car tomorrow.