New to Lowering....help

[Leroy-B1]

Have a set of drop spindles made by Belltech...put them on and the top dodn't fit as it should and had to add a washer and neither did the tie rod end....my question is this changed truck from 6-lug to 5-lug using 71 parts...bought second hand spindles that were supposed to be for 71-72 truck...could they not fit because they may be 67-70 type spindles...any help would be greatly appreciated

also lowered 4.5 in front and 6 in back...it seems to want to sail in a curve...am I missing something to make it handle bad...used original panhard bar as it looked as if it was ok, have adjustable one but didn't appear to move and didn't do shock relocators...what yall think