My name is Willie,I have been around Atlas/other slow turners. parts of my life... I belive that to be 675HP......If there is a 6cyc atlas superior, that Im not sure, but if there is, then the 675HP would have to apply to it. And the 8 cyc would be 100 mabey = a little HP per cyclinder......Great Engines...Anyway, thays my take on it....Sincerley Willie.....somewhere on the Tombiggbee River.....