This might be a dumb question, but when Mercruiser rated horsepower on their stock 454, 7.4L engines through the mid-80's and early 90's , were the horsepower ratings given at the prop or crank? Specifically asking about the 454 mag bravo's, MCM 370, 400, 420, 440, 460 etc.
If these are prop ratings what is the loss generally from the crank? 30 hp or so sound right?
Happy New Year to all........