I exclusively use 5501's on my casting rods. Only exceptions is a couple 6501's on my plug rods and a couple 6001's on my old plunking rods. I've caught MANY kings, biggest around 55lbs on a 5501. Never had a problem and never had a drag fail. You'll be just fine, and with 20lb test you'll fill it up to about 100 yards. I'd say you'll be fine, but I'd suggest going up to the 6500, that way you'll have extra line and alot less wear on the bearings (due to high rpms of a smaller spool unloading quicker). I use around 12/15 lb test on all my 5501's. So there's my .02 hope it helps....

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