Hola, Pablo! At the very minimum, you will have to modify the engine cowling, as the F4U-4 has one chin scoop, and the F4U-5N has two cheek scoops, plus the engine is tilted slightly downward at the front by 2.5 degrees, and the cowl is longer on the F4U-5N by 10 inches (25.4cm) because of the P&W R-2800-32W engine with larger turbo-superchargers. The exhaust stacks on each side of the cowling are a bit higher than on the F4U-4. The cockpit is raised slightly higher on the F4U-5N. The .50cal machine guns are gone on the F4U-5N (unless you have the F4U-4B kit, which will have the 20mm cannon), and 20mm cannons are used. A radome is on the right wing of the F4U-5N, and flash suppressors are on the muzzles of the cannon. There is also a center-line bomb rack in addition to the two inner-wing bomb racks on the -5N. All of the outer wing panels are metal instead of fabric-covered on the -5N.
Hope this helps. Good Luck with your project!
Gary Mason
Devil Dawg
On The Bench: Tamiya 1/32nd Mitsubishi A6M5 Model 52 Zeke For Japanese Group Build
Build one at a time? Hah! That'll be the day!!