The Rover straight 6 is an interesting one. Actually a Triumph engine developed from but sharing little in common with the OHV straight six and originally planned as a replacement for it in the big Triumph range. Valvegear has much in common with the Triumph slant family of engines. Bottom end is massively strong. Reputedly had to be de-tuned as they easily made similar power to the RV8 in standard form and risked cannibalising sales of the up market models.