you can patch the broken drain with fiberglass and resin. scuff it up and then lay the mat on it and resin it.
there are reproduction boxes available now.
the original evaporator core is much nicer then the reproductions. you could have it pressure checked or do it yourself with either a pump or vacuum.
the reproduction heater cores match original pretty well but you need to check it also before install they are known to be defective New so check the new one for leaks now before installing all that and loosing your mind.
you might want to contact a radiator place and ask them if they can pressure test an evaporator and make sure a heater core is good before install.
contact DON at ohiomustang.com OMS on this board and see if he can help with a box if you do not want to patch it or to ask about the reproduction boxes.
the original flappers in the box had foam glued to them. this reduced air noise inside the box, but the foam sucks in moisture and rots the doors out.
you will also want to inspect all your vacuum motors for leaks with a hand pump. they do not reproduce them so if you need to replace them contact don or you have to search ebay and take a chance.
the reproduction seal kits for these boxes is JUNK! they do not fit at all save as much of the original seals as you can then either order new sheets of closed cell foam off amazon and cut to make new ones or use the JUNK reproduction seal kits and cut them up for the seals you need. SAVE THE COWL HAT FOAM SEAL if possible it is a VERY thick piece of foam and they don't make it so save it.
i took apart all my flapper doors media blasted them, coated them in rust proof paint and then glued the new foam back on as per factory.
there are lots of parts and details in the box so document everything and do your best to collect all the parts you need before re-assembly.
there are external mechanical vacuum switches and some electronics that need to be checked.
the electronics monitor the temp of the evaporator core if it freezes the switch kicks off and shuts off the compressor or it will lock up and can stall the engine or cause damage to the belts and pulleys.
the final test will be done by the A/C service to make sure the controller is working and kicks the compressor off.
with A/C you don't mess around you replace EVERYTHING or you will be taking it apart over and over to make repairs at great cost.
this is where is gets really expensive. Hoses, fittings if missing and compressor.
I made this mistake and it cost me 1000$s of dollars extra. I did my a/c system about 9 years ago now, i took a shot and reused my original compressor and it was BAD. it cost me another compressor and another Dryer and another A/C service. the system was working for a month then down again for 2 years until i got everything to try again.
another issue is the Duct fan. the reproduction Duct fans do not run the same as original they are slower and have electrical noise issues. the original duct fans work much better but have worn brushes this massively increases amp draw on the main switch and can burn it up or burn some wires. i'm sure you will find the main climate control fan switch has melted on the ground connection and usually the wires look pretty bad also around that connector. so it becomes a catch 22 of keeping the original fan or trying to find a better one or taking a chance with the made in china reproduction duct fans.
keep note of all the vacuum connections they are colored with stripes, white, blue, red, purple, etc. that goes to all the vacuum motors in the system there is a vacuum diagram on how they assemble.
the main vaccum manifold that plugs into the back of the a/c slider controls needs to be inspected it is all rubber and can be dry rotted and worthless.
as you can see it isn't a slap together job and can be quite time consuming and expensive depending on condition.
you have a no-op for over 20 years system that sat in a barn and got mice in it so everything is suspect and must be looked at one at a time.
classic air will have the hoses for the system, they will not have missing connectors or hardware. the dryer and condenser can be purchased from various vendors. the evaporator and heater core as well, however i would reuse the original evaporator if possible and it is tested and checked.
the internal parts for the box are not reproduced as far as i know, the motors are not.
many people decide the original system is too hard to repair so they gut it and go with a complete classic air retrofit kit to put the a/c back in the car.
this will be a cheaper option and faster but it will require work to install as it is not OEM. it will lower the value of the car but just restoring one of these can cost more then the car is worth sometimes.
I cannot quote the brands but they make cleaner for your home Heat Pump system which is really the same. Do a search I have some pictures of what I do to keep the mice out of the heater box and cowl. You cannot see it when installed and those little critters love heater boxes and cowls.Would you try to salvage this? Core is actually pretty sound, save for the deteriorated fins as shown. Still have to pressure test to be sure... Someone know the best way to safely clean the aluminum of the previous heater core leak leftover?
......I cannot quote the brands but they make cleaner for your home Heat Pump system which is really the same. Do a search I have some pictures of what I do to keep the mice out of the heater box and cowl. You cannot see it when installed and those little critters love heater boxes and cowls.Would you try to salvage this? Core is actually pretty sound, save for the deteriorated fins as shown. Still have to pressure test to be sure... Someone know the best way to safely clean the aluminum of the previous heater core leak leftover?
The gauges and vacuum pump to do your own system cost less than taking to shop one time so just buy them and you can do your other vehicles also.
Also look at Duracool. The company is Canada based and I ordered the refrigerant and going to use in my car even though it is not legal in the U.S.. It is much more efficient the any other refrigerant and takes much less. I have had to drop working on the cars until my garage is up and going so cannot give first hand review. They supply new lubricants for system and they sell kits. Air Conditioner is just like anything on a car just nuts, bolts and very little electrical.
Like you have been told test new heater core I have found two bad ones and one was just last year and it was a NOS Ford core.
If you do restore a case walnut shells and low pressure in blaster works pretty good for cleaning then coat with semi gloss clear and it will look like NOS. Be very careful taking the doors out or getting the shafts out that are rotated by the vacuum. I made a metal piece to put between the flapper and the fiberglass housing to spread out the force. They get horribly rusty so soak them down with penetrating oil. I prefer using Molasses tank to de rust takes a couple weeks but gets it very clean then coat with your choice of rust preventing coating. You can test all the vacuum with your brake bleeder if it holds a vacuum it is good, simple quick and costs very little.
I cannot see how it would cost thousands to rebuild and air system unless just total junk. The seals on the compressor shafts are quite unique having to hold pressure in all directions.
Maybe in about a month I will have my cars in my garage and I can work on them again.
Those fins are the worst corroded I have ever seen mice pee for sure.