AC upgrade on 73 Sport

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supertruck

supertruck

Unretired Old Fart stock car racer
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Vehicle is a 73 Dart 340 Sport, factory AC car. I'm upgrading the AC as part of my rebuild. Already have a Sanden compressor that came with my CVF pulleys. The heater box has been rebuilt with new heater core and evaporator. I was looking at the Classic Air upgrade and told them I needed all the underhood parts except the compressor, and that the interior was rebuilt with a new stock evaporator. The guy said I had to replace my new evaporator with one of theirs. Not being an AC guy, can anyone tell me why I have to replace a brand new evaporator as part of the upgrade?
 
just ran into same problem on 74 duster,classic air wanted over$1600 for everything.,i bought a 90 dodge ramcharger condenser, drier,and compressor,new, went to Napa, showed them the block style hoses at compressor,drier,and condenser, then showed them the evaporator and expansion valve, they ask what type of freon, i told them 134a, so they made up the hoses, both high pressure and low pressure with valves to vacuum the system and valves to fill system, all total using used a/c brackets off 90 ramcharger, i have about $450 in my entire a/c system. NAPA charges were $160 for hoses ,crimping and aluminum fittings to evaporator and expansion valve.I was told that condenser off 90 ram wouldn't fit, i will say it took a little work but got it in ok. Only problem my 74 alternator wouldnt fit the 90 ramcharger bracket, so i upgraded to a 90 amp alternator and did the bypass and put a volt meter in place of the ammeter gauge in the cluster, which for meter and alternator was an extra $80
 
AC components should be sized to each other for optimal performance. Although it may work with mismatched components, it will work better with the correct parts.
The newer evaporators and heater cores are much more dense than the old ones. They have smaller passages and 2-3x the fins.
 
MoparMike1974 said:
AC components should be sized to each other for optimal performance. Although it may work with mismatched components, it will work better with the correct parts.
The newer evaporators and heater cores are much more dense than the old ones. They have smaller passages and 2-3x the fins.
Click to expand...

If the system uses a TXV (thermal expansion valve) the sizing is not nearly so critical. You need to learn to charge with superheat/ subcooling readings and just be careful when you charge it, monitor things. I admit this can be difficult without a huge fan to provide "fake highway airflow."

I bet it would work fine
 
supertruck said:
...new stock evaporator. The guy said I had to replace my new evaporator with one of theirs.
Click to expand...
no you don't. did my 73' and left everything south of the firewall stock. works awesome. i used the Bouchillon brackets and bought everything piece meal from here. also had a mobile A/C repair guy come to the house to run the lines and charge it.
 
Thanks for all the info guys. Could not complete my work without FABO members.
 
The reason i used a 90 Ramcharger condenser was, size, it was the tube type and was about 1/3 larger than the actual condenser that came on car, Air at vents on R22 systems comes out of vent at 40 degrees , but using same size condenser and a piston type compressor you get 48 degrees when r22 is replaced with 134a, but with larger condenser and rotary compressor, and correct size hoses i get 42 degrees, i only drive the car on special weekends to car shows. As far as mismatch all my parts are for a 90 ramcharger including compressor, lot less space to cool in a Duster than a Ramcharger, and Napa was good enough to look up the correct hose size for evaporator,only difference ,the evaporator on the 90 ramcharger was 2 inches taller than the 74 duster, and wouldn't fit the airbox, so i had to use a 74 evaporator .
 
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Budget underhood AC retrofit.
May be some info for you here. I used truck parts with an aftermarket cross flow condenser in my 74 Duster with stock under dash components. It worked great! I do have more photos if there is something specific you want to see, I may have it.

Cley
 
Thanks Cley, I'll definitely check it out, and probably have some questions for you.
 
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