The 72 Ah battery is actually a 650 CCA battery. The 750 CCA battery is 78 Ah. Both batteries are the same group size, 65. I couldn't believe they shipped my truck with a 540 CCA battery (group 59, 58 Ah). But it only needs to meet Ford cold cranking requirements, key off loads and underhood temperatures. I now have the 650 CCA battery in my truck.
If your truck came with a battery blanket, make sure you still use it.