lifting a 67 k10

[killa98z]

hi i would first like to say im new here and this is my first truck its a 1967 k10 short bed and im looking to lift it.i want to either a 4 or 6 inch lift but i heard theres problems with the steering on 1967s it this true.wat can be done. need some help.Second question
it has the rockwell transfer case but i heard that u are limited on ur top speed with this case is this true can anyone help me out thanks john