Small block headers: worst to best fitting. List your experience.

Seems to be a lot of different headers for diffrent small block LA/Magnum 1967-1976 A-bodies and not enough info to go around. If someone has had good/bad experience while installing headers sets with certain options (like power steering, aluminum heads, rack-pinion, etc), maybe we can list it here so everyone can post how it went so others can see their struggles or accomplishments. Part numbers and pics would go along ways to helping some members.