[dwcsr]

Start with what truck this is?

There are many theories on what's best for cooling, 4 core with a mechanical fan to 2 core with a hi performance electric. Cooling depends more on how much heat the radiator will release than CFM passing through it, CFM depends on fan capabilities and can the air get out of the fan efficiently. You look at the back of a high dollar Zirgo that claims 3000 cfm and you wonder how it could possibly pass any air at that CFM while you look at the back of a Taurus or Thunderbird fans rated at approx 2300-2500 CFM and think a hurricane could blow through these fans why is it only 2500.

What radiator type? Cross flow, the old type down flow or a split core.
Brass or aluminum. I prefer brass, The physics are better for heat transfer.

How do you want to control it?
Do you want relays or Pulse width control? can it be controlled by a PCM , If yes does the PCM have hi/lo fan options?
Prefer single fan or dual or just whatever will fit?
Do you plan on running AC?
What HP does it have?

Flex-lite would not be my first choice, OEM if you can get it to fit such as Thunderbird or Taurus or Camaro, Spal

Low profile fans are usually under 1800 cfm so i would question the 2500 rating
what ever fan you choose it needs to have 80% radiator coverage, either in a single fan or a dual or multiple fans, I ran 4 9" fans to get 4000 cfm cooling a 468 BBC here in Texas in 100 degree weather, It looked odd it was a bit loud but it worked and got by all the engine obstacles.