Heading up to Wisconsin for the vintage car weekend, I was worried with a loud ticking from the engine. The local mechanic (Gianni) pulled the valve cover and checked the valve clearances - which should be done on a cold engine. This one was hot, so it not quite proper, but we found two loose rocker arms, and were able to get them back to the specifications shown by the other valves. (On an average, seems the valve lash was about .05mm tighter than when cold, but that is just a guess).
Here is a shot of the rocker arms and the pillow boxes that hold them. You can see the pushrods up top in pairs, coming from the cam in the valley of the "V". Then the clever rocker arms, in pillow boxes that are angled, so that the intake valve is rotated about 45 degrees closer to the intake, and the exhaust valves are on the bottom, close to the exhaust manifold. This way of rotating the valves was De Virgilio's clever improvement, first implemented in 1952 on the second series B20, and then used for all subsequent B20 and B24 engines. This car has the two single Webers as standard (the one for this bank is visible) and a special tubular exhaust.