One of the 4by rags did a long bed chevy some years back. They used 12" lift springs,+ a 3" body lift and still had to trim just to clear 44's. So Im gunna say NO 54's wont clear.
They didnt have any problems until they went off road, it was then they had to trim the fenders. MTBLAZER89 is correct the opening just isnt big enough, its like a 12" peg in a 8" hole.
As for RIPPEDK5, you need to recalculate to take in the steering movment, then figure in axle movment both up and down and front to back. As your springs compress the axle will move up and back, now throw in a full lock turn, and something is gunna rub.
Balzer