I was just adjusting the valve lash on my freshly rebuilt 261 last night, which has a new rocker arm assembly and new valves. I was using a flat feeler gauge to set the lash and I was not sure if I was doing it correctly. The mating surface of the rocker arm is concaved and the valve stem if flat, so if you slide the feeler gauge straight in the concaved rocker surface looks like it might cause a wider gap setting than if you just used the corner of the feeler gauge at where the stem meets the rocker arm. I set the gap using to corner of the feeler gauge, which I felt would be more accurate. How do you guys set your valve lash? With the lash set in this way my push rods spin freely when the valve is closed. I would think that if you had your valves adjusted so tight that your engine would not start, that you would not be able to spin the push rods.
