Depends...what the issue turns out to be and if it is suitable as a core. Original engine always good to keep if it is, likewise original type of engine is easiest to swap if you already have the brackets, accessories, air cleaner and shaker, wiring and plumbing to suit that type. Depends what replacement options are around. I'd be looking to freshen up what you have based on what's typically required. Easy to double the hp but look stock during a simple 403 rebuild.