I did it! now I have a 1993 5.0 FI comlete engine with its serpentine belt and compressor and all 1993 accessories with custom made a/c hoses, new condensor, new dryer, original a/c & heater box inside car (does not leak) in my 1970 factory air car. I have had the a/c system vacuumed and leak tested and re-charged - the a/c will cool super but soon it pops the high pressure relief valve. Any thoughts on how to stop this. The 134 freon amount has been adjusted to the proper amount vs r12 and now I have purchased from classic auto aire a new expansion valve but have not gotten it back together yet - I don't know if this will solve the problem but I hope so - I'm just asking in case this does not work. Somebody said something about an orifice tube system on later model cars if this does not cure it - what is that?