Complex sentence: Most replaced M4 gun with the lighter T13E1, designed specifically for the aircraft, however 20 odd H series completed by the Republic Aviation modification center at Evansville continued with the M4 and two MG nose armament.
Split into simpler sentences: Most replaced M4 gun with the lighter T13E1, designed specifically for the aircraft. However 20 odd H-1 block aircraft completed by the Republic Aviation modification center at Evansville continued with the M4 and two MG nose armament.