What else, overheating

Mine did that last December. No 12V to the fan relays. As soon as I started to move it to the basement, the fans started. Now I have a couple of breakers next to the battery and a couple of wires to plug in the fans. Someday it will stay broke long enough for me to find it.
Even with the relays bypassed and the fans running constantly, it does not like idling for long periods in the Atlanta summer. I do have a large Griffin radiator and vents in the hood. Stock fan motors, but larger blades. Eventually I may lay the radiator forward and install sucker fans.
Your cheap fix is DO NOT IDLE for long periods

I've got a '73 L in California. I have a heavy duty radiator & layed it forward for easier access, put in 2 sucker fans (no shroud or hood vents), installed an aluminum high perform. water pump, use 20% anti-freeze with Redline Water Wetter. I can use the A/C in traffic and the engine runs one needle width above 190.

#1: There may not be anything wrong. But even a stock Pantera won't sit and idle with only one fan on. Be sure both fans rotate the same (proper) direction.
#2: the stock rad cap often doesn't seat on the neck of the surge tank tightly. The problem is, the base of the neck is too rough to seal, and the Italian neck is too deep, which relieves the seal pressure. The fix is to remove the surge tank, take it to a rad shop and have them take the Italian neck off. Have a US-made neck soldered on and the cap problem goes away.
#3: bleeding air out of the system is tricky, requiring lots of time and patience. It helps if the rear of the car is jacked high in the air during the bleeding.
There are other, more expensive and exotic fixes if those don't fix it.

Visit my Cooling article at: http://geocities.com/provamo72/

Chuck