[Roadsters] Question on conversion

[BARTERDUDE at aol.com]

The link the shows a 1962 Fairlady race car shows this as HP rating:
 
Engine Max. power

59kW (80PS)/5,600rpm
My Single Carb, which this doesn't show the carb setup for the 1962, but it 
 is rated at 77 HP, when they added the dual carbs it became 85 HP.  Don't  
think back then there was anything changing the HP rating between Japan and 
US,  so wondering why it is showing 80 HP when converting 77 HP to KW it is 
56.63 or  57 KW if you round up?
 
Any thoughts or insights?
 
Gary Lasater  - Parker CO
founding member _www.WyCROC.org_ (http://www.wycroc.org/)  / 
_www.ZRoad.org_ (http://www.zroad.org/)  
1963 SPL310-00161C  (Single Carb)
1963 SPL310-00289B (Single Carb)
1964 SPL310-01289
1967  SPL311-09144