What did the Marines change on their Corsairs to operate from land bases?

The F4U's long nose severely restricted visibility, especially with the aircraft on the ground. It also limited forward vision during the critical landing approach: on short final, the end of the runway disappeared entirely from the pilot's field of view.

The pilot's seat was raised 7 inches (180 mm). That modification was combined with a new canopy and a 6-inch (152.4 mm) lengthening of the tailwheel strut. Together, these changes allowed the pilot to see better over the long nose.

VMF-124 was formed on September 2, 1942, at Camp Kearney, San Diego, California. It was the first Marine squadron to fly the Vought F4U Corsair during World War II. It was declared fully operational on December 28, 1942, even though its pilots had logged an average of only 25 hours in the aircraft. A dozen of the unit's F4U-1s, under the command of Major William E. Gise, reached Henderson Field — codenamed "Cactus" — on February 12. The squadron landed on Guadalcanal on the morning of February 12, 1943, led by its commander, Major William Gise. It flew its first mission before lunch that same day: twelve F4Us escorted a PBY Catalina on a 230-mile mission to pick up two pilots shot down at Sandfly Bay, Vella Lavella.