R134a is all that is available If you have an R12 system You have to retrofit to R134a I didn't go through the hassle of changing the entire system to r134a I just recharged the system with the new freon and it's working just fine. The coolant even last longer.
It depends on what kind of freon you need.
R-12.
R134a
R134a
R134a
R134a
R134a
R134a
It was built with R12, but will need to be retrofitted for R134a.
Was built for R12, should be converted to R134a
A 1998 Chevy Camaro uses R134a.
If you asking what type of Freon is in a 1993 Aerostar, that would be R12. If you need to get it recharged, you will need to have it converted to R134A system since R12 is no longer available.