Sorry doing this from my phone won't let me search. Have a 75, 390 with a heavy duty radiator, was wondering what the cooling system capacity is. That and how much of a B*%ch is doing the heater core in this? Has ac, looking for a thread on this. Thanks in advance

 

If you have factory A/C it can be a real PITA. Here's a good link. While you're in there, check the blower motor. They're relatively cheap and now would be the time to change it too.
I'll check on the cooling system capacity.
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Owner's manual says standard cooling aprox. 19.6 quarts, extra cooling aprox. 22.3 quarts and super cooling aprox. 23.9 quarts.

 

That's what i was afraid of, has the factory ac. Gotta do it though, is driving me crazy not having it. I need to tear the whole truck down but i constantly need a truck...