82 Nighthawk 750 vs 81 CB750

[bigiron59]

I have a question about the difference between an 82 Nighthawk with the 750 dohc engine vs the CB750 dohc engine. The bore and stroke on the two engines are the same, but the nighthawk is listed to have “.1” more cu. in. of displacement. The nighthawk has a compression ratio of 9:3:1 while the CB has a compression ratio of 9:1:1. Does the head on the nighthawk have more clearance than the CB? Can anyone verify this information, or are they the same engine? (I am referencing my info from www.motorcyclespecs.co.za)

 

[Loose Chain]

I own a '81 CB750 Custom and an '82 CB750 Nighthawk. Same engine. The Nighthawk engine is black and the Custom is silver.