I'm the one that R&R the 460, in the posted link.
No need to pull the engine out of the dog house. That'll just get every thing mucked-up inside.
My 460 block is taller and wider than your 454. Yours will come out the front easier than mine did.
A few 454s had intake manifold failure that hydro locked the engine. And some had head gasket failure that hydro locked the engine. My first encounter with a hydro locked 454 motorhome was in 2002. Broke a piston and bent a rod. You're not the first to encounter this problem.
Richard