sorry if this has alredy been asked, i did a search... manny searches, and came up with nothing. i read someware that someone converted their factory air evaporator to a orface tube design from a newer truck, like an 87 blazer or truck. my question is how hard was this and what year and model evaporaror are you using? thanks for anny help... i just got a 69 c10 long bed and it has factory air and id like to do ths mod as i know the orface tube system like the back of my hand and can get it blowing ice out the vents