454 big block engine swap

Hello,

I acquired a 1998 4 bolt gen vi 454 big block Chevrolet. I want to put it in my Chevelle SS 1968. I want to get 500 plus hp ou to fit. What top end kit do you recommend? I currently have a stock 396 in my Chevelle. Ill be keeping it as a spare as it is a matching numbers engine. I don't want to do anything to the block.