The 454 Chevy has been around so long that it has become a legend in its own time. It is a VERY good truck motor. Keep in mind that it is NOT perfect, just one of the best around.
I think you are asking the wrong question. Any rebuilt motor is only as good as the materials and workmanship that went into the rebuild. What pieces were replaced? What machine work was done and by whom? What is the record of the rebuild shop? What is the warranty? These are more important questions than the question about the engine size and brand.
What year is the RV? Some of the earlier 454 exhaust manifolds were prone to cracking and we had some starter problems due to heat. This engine needs the high torque starter and the heat shield installed at the solinoid switch. Like the previous post stated the rebuild is no better than the mechanic that did it!! Do you know the builder and can you get a list of installed parts? The 454 was a vere good engine IMO. Good luck