Are you fishing a river? from shore? from a boat? salt water? makes big difference in gear needed. I use different rods when fishing from shore or fishing from a boat. Depends also on whether it is a small swift river or wide open salt water. Have caught kings on trout gear in saltwater and used 100 lb. line when shore fishing a whitewater river overhung with brush-- and broke line! Didn't break the 8 lb. (or 6?) line in salt water where we could follow the salmon in a boat.
That said, my rig for reds in a river is a 10'6" Skylitz 1062M rod from Tillamook Sporting goods, with an Ambassadeur 6501C4 filled with 40 lb. fine diameter synthetic braid and 14-17 lb. leader. I use leader that heavy because incidental hook-up of kings is common. For back-up I have a 9'6" medium spin rig.
For jigging salt water and fishing smaller rivers from shore for kings I have a 9 foot Berkley A92-9XH rated to 50 lb. line and up to 3 oz. lures. Daiwa Sealine reel with 50 lb. braid and whatever leader seems appropriate. Have mostly used 15-20 lb. leader in salt water for big kings, 25 when fishing a river from a boat, to allow a b it of margin for abrasion. 40 lb. leader for kings from shore in rivers big enough for room to play and follow the fish on shore.
Kayak fishing for salmon of any kind I use shorter rods, 7 footers whether spin or bait casting.
