BMEP, Brake Mean Effective Pressure is a means of rating engine efficiency. In the article I'm hunting for various engines from the history of F1 were rated. Unlike BHP it doesn't rely on RPM and so rates the actuall efficiency of the process. What was most interesting was that the Vanwall engine actually rated the highest of all for BMEP. Not by tons mind you but still highest.
Unfortunately Comcast swallowed my bookmarks before I had a chance to really get into the article. Unfortunately Comcast's version of IE has usurped my net connection and it's at best balky when trying to search.