Welcome Cilina,
I would double check what engine it has in it.
I am a Detroit Diesel fan and have never heard of a "Detroit 455".
If you look about this site you will find MANY discussions of the merits of different body styles. The short version is:
Conventional (dognose): Easiest to service. Least living space for given bus length
Front engine (FE): Hardest to service. Most living space for given bus length. Can be noisy & hot in the drivers space.
Rear engine (RE): In between Conventional and FE as far as living space for given length and ease of service. Engine is far from the driver. Little or no noise & heat issues.
I love my RE.
Value of a bus depends significantly on condition & mileage. Tell us more about the bus?