I need to remove the engine and tranny from a donor car soon. Ac system works great and will sit for maybe a year. How do I store it so it doesn't get messed up?
Do I need to seal it up tight and if so how?

If at all possible, you should leave the A/C system closed and intact. Sometimes you can unbolt the compressor, swing it or hold it out of the way, then remove the engine without having to disturb the A/C system.

If you do have to remove the system, first have the refrigerant evacuated properly. DO NOT just release it off into the air. Not only is it illegal, but it's a big waste. The recycling system works, and as long as people don't piss away their Freon, there'll be plenty of it for our older cars for a long time to come.

You'll want to keep the system CLOSED to the atmosphere. Easiest way is usually to put the compressor and whatever else you took apart, back together in the empty engine bay. You can use stiff wire to hang the compressor. If that's not possible, find or make secure plugs for the open ends.

Try to store in a DRY place.

When it comes time to reinstall, you will definitely need a new filter-dryer.

Thanks.
The system needs to be pulled out of the donor, so I'm wondering about firewall connection.

what type of gasket material and "Caps" can be used?
Is this the famous Dan Stern?
I used to read your articles on Tailfins.
Headlights, etc!

Go to an auto workshop that does A/C repairs (you'll be there anyhow to get the Freon sucked out), tell them you have to open the system and want it to stay clean inside, and ask them for some caps. They should have them lying around from new hoses and other parts they've installed. Otherwise, you can wad-up some electrical tape and stuff it in the hole (leave yourself a handle!) and then tightly rubber-band a plastic sandwich bag or some saran wrap overtop of that.

Dan Stern? Yes, that's me.

"Famous"? Lies. I'll deny it all.

Headlamps? Yes.

Thanks again Dan.
Yeah I was looking for the headlamps article (I thought I printed it out) and couldn't find it.
You should publish ALL of your tips for us A-body/mopar freaks, I'd buy it!

Here's a start.

Here's a picture of the inside of a Chrysler RV2 A/C compressor that otherwise looked quite good on the outside.
It's very important to have the AC components sealed up tight with no moisture inside.

You are looking at the inside of the compressor crankcase and can see the crankshaft, ball bearing, and piston/rod assemblies.