800 to 900 CCA will be fine and alot better in cold weather.
"Cranking Amps" are the amount of amps required for the starter to crank the engine. Automobile batteries are measured in "cold cranking amps." That's the amperage capacity of the battery in cold weather.
For the 5.4 liter V8 engine in a 2001 E-350 the owners manual shows that the optional battery is 750 cold cranking amps ( they also show that the 6.8 liter V10 engine has a standard battery that is ( 650 cold cranking amps ) and the optional battery is ( 750 cold cranking amps )
The cold cranking amps that are required to start your Ford 2.5 liter engine is dependent upon the outside temperature. 450 cranking amps are required at a temperature of 32 degrees.
I would recommend 500 minimum.
800 to 900 is plenty even in colder weather.
If you live in a cold climate the more the better.
4 cylinder engine / BCI group size ( 96R ) / 500 to 590 cold cranking amps ( CCA ) V6 engine / BCI group size ( 40R ) / 650 cold cranking amps
A 12 volt battery with about 600 cold cranking amps works well. A little bigger if you live in a cold climate.
It requires a group 78 battery. I do not know the physical dimensions of the battery. You will need to get one that has the proper cold cranking amps.
There is no better, but 800 is more cranking power that 650.
910 cranking amps 700 cold cranking amps
cranking amps or cold cranking amps Group refers to its physical dimensions.