iso-butane conversion from r-12 for 69 camaro

[inetquestion]

I'm interested in converting the existing AC in my 1969 camaro to an iso-butane system. Can someone who has done this to any r-12 system give me some pointers on what equipment I will need to change out, and where to buy some of the materials? I found a fuel cannister made by MSR which looks to be a good source for the refrigerant: http://www.msrcorp.com/stoves/fuel_blend.asp but would definately like to get a second opinion on that as well. Should I change the expansion valve to an r-134 from the current one? After the systems has been vacuumed down and I start adding refrigerant, how do you determine how much to add and when to stop? If anyone has suggestions on how to tap the MSR cannisters or modify an existing fill kit that would be helpful as well. Last but not least does this conversion pose any danger to the existing system? What I mean by this is does changing the refrigerant cause the existing seals to deteriorate due to the change itself?

Regards,

-Inet

[skibum1111]

Personally, I'd change the orings and convert the system to 134A as you don't have to change anything else, the compressor, expansion valve, evaporator and condenser are all compatible. Plus, isn't butane rather flamable?

[CamaroRS92]

There are several products specifically for R12 systems that take place of R12 without doing aything except adding the refrigerant to the system same as you would add R12 to an undercharged system
DuraCool
Freeze12
Not sure about Freeze12 but DuraCool is a propane base product.