11:40's was the round about number in the late 80's with them using a Solid MP grind. I have a set now on the 72 and will use them until I get bored and put my Cranes on it but that is down the road....
the 273 rocker has way less mass to move. they are good for any cam. the aluminum rockers have more mass over the valve, requires more spring pressure to keep valve float away.
