[Sirrotica]

The heads are listed as having different size valves, as well as compression ratios:

094 1.88 intake 1.66 exhaust 8.6 CR

140 1.92 intake 1.64 exhaust 9.2 CR

I'm fairly certain that they aren't identical castings, and machined identically.

Having worked in a Pontiac dealership, the factory was having problems with breaking valve springs in the transition from 1966 to 1967 due to the valves being too short. The springs needed to be taller so they didn't fatigue quickly.

Also since I've attempted to run 1966 valve covers on 67 cylinder heads and the rocker arms will dimple the valve covers as soon as you start it. The valves I believe, have longer stems on them, necessitating the long pushrods to get the valve train geometry correct.

Bart. I'm not sure where you're getting information from 55-64 for the most part of conventional passenger car engines, oiled the rocker through the hollow rocker arm studs. The OEM rocker arms had no oiling spurt holes at the pushrod pivot point. The OP is saying the rocker pivot balls are dry due to the absence of spurt holes without hollow rocker studs to oil them.

Having taken dozens of these cars apart, and making a living working on them I've seen this dry pivot ball happen when people start mixing parts that were never engineered to work together.

That's what I've encountered, I'm not going back and forth to argue about it, I've listed what I know from my experience, feel free to list your experiences with mixing, and matching early to mid 60s valve train parts.