You are exactly right, key word (idle) When you run steep gears say 3.91's and 4 speed the R's are usually up above 3000 most of the time, I've gone to the dragstrip and shifted at 6000 RPM's 4 runs 20mins. apart. I think without the
oil restricters the
oil pump would have come dangerously close to cavitating. On the flip side there's FE's out there with well over 100,000 miles on them and still going but they seldomly see anything over 3500 RPM.