354 or 392? Hemi? Questions?

Hey guys thanks. I'm hoping to slap a cam in it and a set of headers and when money provides a intake. I'll take pictures along the way to keep you guys updated!!' hoping for 300-350hp 400 torque it all depends on what hemi this guy has... He said a old 50s hemi... I assumed 392 he said ya I think so.. Gonna have to go take a look