I have a lot of components removed from trusty rusty at the moment, and decided that before I close up, I should check the chain stretch. What a surprise I got. Have a look at the front cam bearing tower of the left head - someone in the past found that the timing mark didn't line up, and ground it off, and scribed a new mark.
So obviously I couldn't check chain stretch by the quick method of lining up the marks. I used the valve lift method, and found that :
The left cam is 8...