12 Valve In place of a 24 Valve?

[pro99]

I am looking to put a 12 Valve in my truck and would like to know who has done this. My truck is a 99 with an auto trans 4x4, what do I need as far as parts to perform this task? I need to get my hands on a 12 valve motor to start or a totaled out truck so all help will help out.



Thanks Charles