From wiki “Throughout early 1942 Leroy Grumman, along with his chief designers Jake Swirbul and Bill Schwendler, worked closely with the U.S. Navy's Bureau of Aeronautics (BuAer) and experienced F4F pilots,[13] to develop the new fighter in such a way that it could counter the Zero's strengths and help gain air command in the Pacific Theater of Operations.[14] On 22 April 1942, Lieutenant Commander Butch O'Hare toured the Grumman Aircraft company and spoke with Grumman engineers, analyzing the performance of the F4F Wildcat against the Mitsubishi A6M Zero in aerial combat.[15][Note 3]BuAer's LT CDR A. M. Jackson [Note 4] directed Grumman's designers to mount the cockpit higher in the fuselage.[18] In addition, the forward fuselage sloped down slightly to the engine cowling, affording the Hellcat's pilot good visibility.[19]”
https://en.m.wikipedia.org/wiki/Grumman_F6F_Hellcat
This was still with the XF6F-1, with the R-2600 engine