I swapped a 350 sbc into my Camaro and i dont know what lines to hook up for my heater to blow out of the vents...i know that the default setting is defroster when no vacuum is there but i dont know how to hook it up...any body have any clue?

 

if those plastic lines break no matter what the heat will not blow out the vents mine broke as well an all i have is the defrosters but i can tell u is one of them hooks up to full vacuum an i believe the other hooks up to a part throttle vac source

 

there should be 2 plastic hard lines coming out of the firewall along with the ac wiring on the passanger side. one of those is the supply line to the ac controls in the cabin. and gets hooked to full manifold vacuum. the other is for the heather diverter vavle. if you got rid of the heater diverter valve then you can just cap it off. without a vacuum supply to the ac controls, it wont switch off defrost.

to determine which line is which you hook vacuum up to one and see if the ac will switch off of deforst. if it doesnt then you got the wrong line. you have a 50/50 chance of getting the right one first try...