If I remember my A/C classes correctly, you will also want to swap out o-rings, and the reciever/dryer. Over time the dessicants (sp?) will consume all of the moisture that they can so it will float freely around your system causing problems. The oils between the two types are also different. The two types of systems use different types of hoses as well. IIRC, the new systems use Galaxy hose.
Sorry, trying to remember classes that I took years ago.
