KZ650-750 Swap

Just bought a 1977 KZ650 last week. New to the forum and was wondering if anyone can shed some light on my plans. I originally had wanted to bore it out, but as i understand the kz750 engine uses the same block but its already bored out from the factory. Has anyone done a top end swap on these bikes? Or is that a waste of time when i could just swap the entire engine out for a 750 and get the added benefit of a taller fifth gear?

A 750cc should bolt right in. You can also use the same exhaust. Bob

Thanks Bob I appreciate the tip. I'll start looking for a 750cc to do the swap.