AC parts from an 81 into a 74.

[rumblebox]

I'm buying a running 81 C20 just to pull the 454 and a few various parts for my 74, including any AC components required to get the factory AC working again. I definitely have to use the compressor and hoses, but does everything else switch over too, like the blower, switches, control unit, evap/heater cores, etc?

 

[MadOgre]

Your 74' came with A/C ?

 

[rumblebox]

Your 74' came with A/C ?

Yes.

My uncle did the 454 swap in the 80's and never put AC back in it.

 

[MadOgre]

Yes.

My uncle did the 454 swap in the 80's and never put AC back in it.

Well I don't know if this is what your asking but if the firewall holes are the same then you can swap every last piece from the 81 into the 74

 

[chengny]

Go here to Classic Parts. It's their Misc AC parts list for 73-87 Chevy/GMC trucks. They are generally very accurate about parts interchangeability between years and models. I did a quick scan of what they have - and it looks like you may be able to use a lot of the 81 parts in a 74:

http://www.classicparts.com/Misc-A_C-Parts/products/379/1/0